Reference Work Entry

Encyclopedia of Medical Anthropology

pp 353-360


  • Elois Ann Berlin


The digestive tract begins at the mouth, transits the esophagus, stomach, small and large intestines, the colon, and terminates at the anus. The digestive system is the greatest avenue of transfer of elements between the human body and the external environment. While the respiratory system serves the vital function of transporting oxygen into the body, which is key for cell metabolism, the digestive system transports many nutrients and other substances that directly affect body structure and function. These beneficial elements are sometimes accompanied by disease causing agents or organisms. This physiological reality is reflected in the epidemiologic patterns of disease and health concerns cross-culturally.

Ethnomedical Perspectives

Ethnomedical systems generally base classification of health problems on signs and symptoms. This does not mean that there is no attention paid to etiology. All explanatory models include concepts of cause, source, and course, as well as palliative and curative treatment, of health problems.1 However, numerous studies have demonstrated that folk systems focus on the personal experience of the disease and that this experience is strongly symptom-based. While the frequency, number, and quantity of liquid stools that define a case of diarrhea may vary from one culture to another, all three signs are generally key criteria for folk diagnosis and classification of diarrheal disease.

Biomedical Perspectives

One natural defense of the body is to flush out the offending substances or organisms. This can be accomplished by increasing the rate of peristalsis to rush the food bolus, which has been liquified in the stomach and small intestine, through at such a rapid rate that there is no time for absorption of the nutrient-containing liquids. Another method of flushing is through increased secretion of fluids across the intestinal mucosa into the intestine. Both produce watery diarrhea. The alternative option to rid the gastrointestinal tract of offending substances is to send it back the way it came, as vomitus. Like any inflammatory process, diarrheal disease may be accompanied by fever.

Ethnomedical Classes or Diagnostic Categories

Folk perceptions and practices concerning diarrheal disease are based on empirical observation. Stools that are watery in consistency are signs for concern although repeated bouts may be required before a decision that stools are not normal and a diagnosis of diarrhea is made. Frequency of evacuation may also be a key variable for determination that a case of diarrhea is occurring. For some conditions that would be classed as a kind of diarrhea, stools demonstrate an abnormal color or consistency, such as the presence of frank red blood, mucus, or undigested food particles. In these cases, watery consistency and/or frequency may not be the criteria of focus. White, yellow, and green are colors frequently attributed to classes of diarrhea. These color deviations generally represent abnormal digestion or infection. Some folk diagnoses also describe a characteristic odor for the fecal matter such as “smells like rotten eggs.” Examples of the naming and classification of diarrhea by two distinct cultures are seen in Table 1 and Table 2. (See also Coriel & Mull, 1988; Hogel, Lwanga, Ksiamba-Mugerwa, & Musonge, 1991 & Weiss, 1988, for analysis and review.)

Other signs and symptoms are also used in diagnosis of diarrhea. The concept of “fallen fontanel” is very
Table 1

Classification of Diarrhea by Tzeltal Maya of Chiapas, Mexico

Class of diarrhea



Distinguishing characteristics


General, watery diarrhea

Frequent liquid stools


Bloody diarrhea

Frank red blood in the stool

Sim nak'al tsa'nel

Mucoid diarrhea

Diarrhea with mucus-containing

Bosbos tsa'nel

Lienteric diarrhea

Undigested food particles visible in stool

T'ilt'il tsa'nel

Droplet diarrhea

Severe straining and small amounts of stool, frequency

Xenel tsa'nel

Diarrhea and vomiting

Frequent liquid stools accompanied by vomiting

Yaxal tsa'nel

Green diarrhea

Frequent green liquid stools, affects infants and small children

Sakil tsa'nel

White diarrhea

Milky white stools, affects infants and small children

Table 2

Classification of Childhood Diarrhea by Shona-Speakers of Manica, Mozambiquea


Distinguishing characteristics


General diarrhea, simple, common, non-dangerous


Frequent and watery diarrhea with vomiting, sunken fontanel, and dry wrinkled skin


Whitish, milky diarrhea, frequently accompanied by vomiting that may also be milky


Greenish diarrhea, accompanied by a lump or pain in upper left quadrant of abdomen


Chronic diarrhea mixed or streaked with blood, also accompanied by weight loss and fever


Milky or mucus-containing


Diarrhea with vomitus that contains brownish mucous

a Information from Green (1999, pp. 112–115).

widespread as is its association with infantile diarrhea. The sinking of the fontanel or soft spot on an infant’s head (one of the first signs of dehydration) is a widely recognized correlate of diarrhea. In folk explanations, the sequence of occurrence is frequently reversed, with the onset of diarrhea being viewed as a consequence of the fallen fontanel which itself may have been triggered by some event or reaction (e.g., startle response). “Sunken eyes” (also a sign of dehydration) are frequently associated with diarrhea in folk systems.

Biomedical Diagnosis and Classification

Biomolecular medicine focuses on the etiologic agent (e.g., bacteria, virus, parasite, yeast) to define most diseases. Since diarrhea is a natural response of the body to expel infectious agents, organisms from any of these classes can produce diarrhea. When stool samples are analyzed to determine pathogens, it is usually the case, especially in developing countries, that a definitive causal organism is not identified. More commonly a “mixed infection” of several pathogenic organisms is present. In those cases that require treatment, the initial step is fluid replacement. Antibiotic therapy, when applied, tends not to be pathogen-specific.

The most important signs include stool characteristics such as quantity, consistency, color, and presence of parasites. The quantity of diarrhea produced is particularly significant in that frequency and volume of stools determines whether the patient will become dehydrated and how rapidly. Dehydration is the primary cause of fatality in diarrheal disease. The more liquid is the stool, the greater is the threat of dehydration. In addition to loss of fluids and electrolytes, the rapid transit time of frequent, liquid diarrhea means that few nutrients are being absorbed from the intestinal tract.

Other key signs that physicians look for include color of stool. Green is said to indicate bacterial infection; bright red is a sign of bleeding from the lower bowel or hemorrhoids. Black (sometimes referred to as “coffee-grounds” effect) is indicative of bleeding from the stomach and upper portions of the digestive tract. The blood is black because it is partially digested. The appearance of the profuse liquid stools characteristic of cholera are known as “rice water” stools. White or very light stool may be associated with hepatitis or other liver problems that impede the ability of the liver to remove the bilirubin from the blood which tends to spill into the urine and stain it a darker color. Absence of stool with a small amount of bloody mucus (“currant jelly” effect) is suggestive of a telescoping of the intestine (due to severe peristalsis) or intestinal blockage (possibly by a worm mass).

Ethnomedical Transmission and Cause

The concept of contagion is a common characteristic of ethnomedical systems and diarrheal events are explained as contagious especially when there is an abnormal outbreak of diarrheas with shared symptoms. Virtually every study that describes folk attribution of cause includes foods (spoiled, bad, prohibited, etc.) as a source. However, air and wind may enter the body to cause any number of illnesses, including diarrhea. Ethnomedical causative explanations for diarrheal disease can be characterized as contagious, disruptive, fatalistic, and personalistic (in which the victim of the disease is specifically targeted).

Contagious. Foods and beverages are probably the most commonly recognized contagious source of diarrhea. Foods may be considered spoiled, unclean, contaminated, or inappropriate for the person, circumstance, or event. Empirically, the foods consumed prior to a diarrheal event are sometimes visible or scentable in the stool. Nausea, vomiting, and a Garcia effect (avoidance of foods and beverages that are associated with prior illness events) may be triggered. Wind and air that are perceived to carry contaminants can enter the body and cause disease, including diarrhea.

Disruptive. From ancient humoral systems comes the most prominent disruptive theory of causation—humoral imbalance. Eating or drinking too many hot or cold foods can cause humoral imbalances that produce diarrhea (as well as many other kinds of health problems). However, disharmony in social and spiritual relations is also a widespread disruptive concept of causation.

Fatalistic. Conditions that occur as commonly as diarrhea in contexts characterized by poor sanitation and public health infrastructure are quite often viewed as inevitable events of life. Most anthropologists and their subjects have developed a tolerance for occasional bouts of mild diarrhea. In most cases no treatment is necessary or sought. Folk explanatory models are heavy with “stuff happens” kinds of explanations. Anthropologists do not talk much about these fatalistic explanations because they are not subject to very interesting analysis. However, they are ubiquitous.

Personalistic. “Why me?” is the cry of the severely threatened. When a familiar condition such as diarrhea turns fatal or life-threatening and/or is resistant to treatment, exceptional explanations must be sought. The high mortality associated with untreated or inadequately treated diarrhea certainly makes it a candidate for this classification. The need to answer why this disease event is extraordinary leads to the search for explanations for why this person at this time is suffering this life-threat. It is now generally uncontestable that any condition, including diarrhea, can be attributed to personalistic causes. It is also clear from the literature, however, that most cases of diarrhea begin with a more mundane diagnosis and move into the personalistic etiology only when treatment fails or signs and symptoms are extraordinary.

Epidemiologic Cycles and Transmission Routes

Most diarrheal disease organisms enter, usually with food or beverages, through the mouth. In areas of high contamination, there is increasing evidence that fecal matter and its pathogens may become airborne. These may be inhaled through the mouth and possibly the nose and reach the digestive system via the pharynx and esophagus. Many successfully transit the esophagus, stomach, small and large intestines and exit the digestive tract in a viable form capable of infecting a subsequent host. The cycle is completed when a pathway from the terminus of the alimentary tract to the beginning, called the fecal-oral transmission, is established. Fecal-oral transmission is usually hand-to-mouth. However, the route need not be direct. The use of human waste as fertilizer, use of agricultural plots as latrine areas, and accidental contamination of soils for food crops can contaminate foods. Unless these foods are adequately disinfected the transmission cycle can be completed when they are consumed. Unintentional contamination of water by runoff of rains or use of rivers and streams for waste disposal can close transmission cycles if the contaminated waters flow to areas where they are used as household or agricultural water sources. Even delivery of water through damaged pipes can result in contamination.

Common bacterial sources of diarrhea include Bacillus cereus, Campylobacter, Clostridium difficile, Escherichia coli, Salmonella, Shigella, Vibrio cholera, and Yersinia. Common viral sources of diarrhea include rotavirus, Norwalk Agent, Calciviruses and cytomegalovirus. Common parasitic causes are Giardia lamblia, Cryptosporidium, Entamoeba histolytica, and the “holy trinity” of the tropics Ascaris lumbricoides (ascaris, a class of roundworms), Necator americanus (hookworm), and Trichuris trichiura (whipworm). General signs and symptoms associated with most common causative agents are shown in Table 3.
Table 3

General Signs and symptoms of some Typical Diarrheal Pathogens


Stool characteristics












Bacillus cereus











Low grade



Runny nose, malaise

Escherichia coli





Low grade






E. coli








Malaise, toxemia





E. coli 0157:H7






Kidney failure possible









May enter blood



Maybe severe






Tenesmus, Maybe rectal prolapse

Stahylococcus aureus



Maybe, severe


Vibrio cholera





“Rice water”; stool rapid dehydration




Low grade



Urinary tract and respiratory infections

Viral Agent





Often AIDS assoc.

Norwalk virus







Maybe, severe




Ascaris spp.


“Currant jelly stools”;






“Pot belley”; worms migrate, intestinal obstruction




Often AIDS associated









Tenesmus, maybe chills



Giardia lamblia




Possible straining

Intestinal gas

Trichuris trichiura






Straining at stool

Rectal prolapse

Some organisms can survive for periods of time outside the human host, either in soils, water, or alternative animal hosts. Champions of survival include Ascaris spp. which can live in moist shady soil for up to nine years, and spore-forming organisms that can survive for long periods and survive drying (e.g., Trichuris trichiuria) and boiling (Clostridium spp.).

Not all cases of diarrhea can be attributed to infectious processes. Vitamin deficiencies (e.g., niacin, vitamin A, and zinc) may play a key role in diarrheal disease (cf. Bhan & Bhandari, 1998) can produce diarrhea as can stress or anything else that compromises the immune system. Other non-infectious sources of diarrhea include nutritional causes such as food allergies and intolerances, lactose intolerance being the classic example. Certain intestinal disorders and diseases can also produce diarrhea. The symptoms in these usually produce chronic or recurrent bouts of diarrhea. Opportunistic infections secondary to diseases such as AIDS or any condition that suppresses the immune system can also produce diarrhea.

Environmental Relationships

As pragmatic observers in close contact with their environment, members of small-scale societies usually can give a good description of seasonal variation in occurrence of diarrhea. Since manipulation of environmental factors is not an option of such societies, these normally remain descriptive observational data such as “There is more diarrhea when the rains come” or “Children get a lot of diarrhea in the summer from eating unripe fruit.”

Environmental Factors. There is seasonal variation in the frequency of diarrheal diseases. This variation is consistent with what we know of the reproductive requirements of the organisms, namely bacteria flourish in warmth and viruses grow best in cold conditions. However, the importance of seasonality is significantly influenced by the general sanitation level (see, e.g., Ackers, Quick, Drasbek, Hutwagner, & Tauxe, 1998). In areas where there is plenty of potable water readily available and quality sewage disposal, the principal transmission routes are disrupted and seasonal variation, indeed overall infection rates, are reduced.

Small children are the least likely to observe good hygienic practices and are, predictably, the most often affected with diarrhea. This likely does not reflect greater susceptibility so much as greater exposure. When infants and small children share a dirt floor or yard with creatures such as dogs, poultry, and pigs, they tend to share their parasites as well. Young children in child-care facilities exchange many infections, diarrheal pathogens included.

Ethnomedical Care and Treatment

Traditional treatments can be divided into those having generally positive effects, those having negative effects, and perhaps those having neutral consequences.

Positive treatment practices include nursing babies and small children as a comfort response. Breast milk is the best resource, especially for preventing dehydration. Human breast milk is relatively high in sodium and sugars, in addition to being a sterile medium containing maternal antibodies and other important nutritional properties.

Household remedies include many plant-based treatments. These usually are administered orally as liquids. This kind of medication would assist in the prevention of dehydration. In recent years, greater attention has been given to the potential efficacy of the preparations themselves, with the result that there is renewed respect for traditional medical knowledge. The use of rice water, for example, for fluid intake during diarrhea is a well-known home remedy. Biomedical practitioners initially reacted negatively to this nutrient-poor fluid. It is now understood that the large molecule starches in rice water are released gradually. This gradual release of starch reduces the risk of worsening the diarrhea through osmotic retention of fluids in the intestine. Many traditional healers encourage healing teas and fluids, sometimes accompanied by specialized prayers and rituals.

The efforts of caregivers to focus on decreasing the output of diarrhea sometimes results in withholding of foods and fluids. There is the danger that a resulting diminished flow of diarrhea is due to dehydration rather than lessening of the disease. This can have serious to fatal results. Purging is a rather common practice for the treatment of diarrhea and carries the potential risk of hastening dehydration. There is always the possibility that folk treatments can have harmful effects, just as biomedical practices are sometimes found to require re-thinking and modification. There is also some risk that traditional therapies may be pursued to the extent that life-saving measures of medical intervention are applied too late or not at all.

Biomedical Recommendations for Home Treatment

For many years, physicians focused on reducing the volume of diarrhea by withholding foods. However, it is now understood that, despite an increase in total quantity of diarrhea, when bland foods and nutritious beverages are consumed, some of the nutrients are absorbed and the patient returns to normal nutritional and health status more rapidly. Maintenance of fluid balance is viewed as the most important home health care measure. Current recommendations for preventing and treating dehydration include beverages enriched with essential salts and electrolytes, especially for children. Most developing countries have distribution programs for oral rehydration solutions (ORS is also referred to as oral rehydration therapy, ORT). Grocery stores and pharmacies carry a variety of flavored rehydration beverages and Popsicles to prevent or combat dehydration. Pediatricians recommend what is referred to as a BRAT diet of bananas, rice, applesauce, and tea. Bananas are a relatively good source of potassium, although not enough potassium is present in normal servings to correct a serious potassium imbalance. Rice has large starch molecules that release glucose gradually. Applesauce contains pectin, which aids in decreasing diarrhea. Tea leaves have been shown to have numerous pharmacological properties including antibacterial, antiviral, anticholesterol, and tumorstatic activity. The first two might be useful in treating diarrhea.

The World Health Organization (WHO) and other international agencies involved in the control and management of diarrheal diseases, dehydration prevention, and rehydration therapy have undertaken many programs and studies to determine the best medical, practical, feasible, and acceptable methods for preventing and treating diarrhea and dehydration. The general conclusions suggest that prevention of dehydration is the best home treatment procedure. However, most studies demonstrate that caregivers have difficulty in mixing the proper amounts of salts, sugars, and water, especially in making the mixture over-concentrated. This in itself can pose a danger for dehydration by pulling water into the intestine through osmosis and increasing diarrheal output. Traditional home preparations of fluids and foods are now encouraged, especially continued breast-feeding when applicable. If feeding, particularly fluids containing nutrients and calories, are continued throughout the diarrheal event, most cases of diarrhea are self-limiting. Traditional healers have also proven to be amenable and effective at promotion of rehydration when trained in preparation and administration of ORS.

Over-the-counter remedies are available for diarrhea. However, the use of antidiarrheals that simply stop the diarrhea can be potentially harmful because of the danger of prolonging retention of an invasive organism in the intestine and providing prolonged opportunity for penetration and erosion of the intestinal lining.

Recognizing when Home Treatment is No Longer Sufficient

If frank red blood is seen in the stool, or if the feces is black or contains pus, then medical consultation is recommended. Dehydration is evidence for consulting a physician and may require hospitalization. Signs and symptoms of dehydration in adults include thirst, reduced frequency of urination and/or dark color of urine, dry skin that loses its elasticity and remains in a pleat when pinched, fatigue, and light-headedness. In children, dehydration is noticed from the top down. First signs are the absence of tears when a child cries, the mouth and tongue become dry, urine flow and frequency is decreased. A child is considered dehydrated if it fails to urinate for a period of three hours. Other signs of dehydration include high fever, listlessness, and pleating up of skin after pinching.

Theoretical and Applied Implications

Much of modern medical anthropology has its origins in anthropologists’ interaction in international public health and medical programs of the post World War II era. Anthropologists, like their medical colleagues, assumed that Western medicine was superior to traditional medicine and that the natural course of things was to replace the latter with the former. The skills of anthropology were needed to gain public acceptance of the new medicine and its practitioners. Both anthropology and medicine have come a long way in the succeeding decades.

Medical anthropologists have dealt with diarrhea primarily from a systems approach, based on theory derived from medical ecology, and to some extent political ecology, biocultural anthropology, including evolutionary and adaptationist perspectives, critical medical anthropology, and epidemiology. Numerous theories have addressed both the proximate and ultimate causes of diarrheal disease patterns. Anthropologists make contributions at several levels as scientists, formulators of policy, and social activists. Some draw on field experiences to argue that the solution is political and/or economic change. Some work to identify such culturally sanctioned treatments and to guide health policy toward encouragement of effective local herbal formulae. Increasing numbers are integrated into epidemiological surveillance, health policy, and health care delivery systems.

Irrespective of one’s theoretical or professional orientation, it is clear that those whose lives are characterized by frequent bouts of diarrhea also live at the bottom of the socioeconomic scale, in settings lacking in basic sanitation and public health infrastructure. They frequently tend to live in marginal areas peripheral to cities or outside economically developed regions. They may inhabit regions of high biological diversity, though population pressures and a shrinking land base are compromising the health of both the environment and its people in increasing numbers of such contexts. When they move to urban areas, they often live on the periphery, both geographically and socially. They gather in shanty towns on the outskirts of cities or in degenerated inner cities where dwellings are poorly constructed and/or maintained and often vermin infested. There frequently exist situations of over-crowding, poor sanitation, and a general lack of public health infrastructure and services. Whatever the specific description of the physical context, the perpetuation of transmission cycles that make fecal pathogens part of oral intake is the first problem in diarrheal disease. Resources, knowledge, and tools for survival is the second. Sanitary waste disposal and an adequate source of safe, accessible water are the key elements to breaking the transmission cycle. Adequate and acceptable treatment should be the intervention of last resort when prevention has failed.
Table 4

Pharmacological Properties of some Plants used by the Highland Maya to Treat Diarrhea


Mode of action in treatment of diarrhea







S. aureus, E. coli





S. aureus





S. aureus




S. aureus (mild)



S. aureus, E. coli, Candida albicans





S. aureus



S. aureus, E. coli, Candida albicans, Pseudomonas aeruginosa



S. aureus, E. coli, Candida albicans



S. aureus, E. coli, Candida albicans, Pseudomonas aeruginosa





S. aureus, E. coli, Candida albicans



a spas. = spasmolytic

b hemo. = hemostatic

Table 5

Genera used to Treat Diarrhea in the Highlands of Chiapas, Mexico, and Other Regions


Some areas or systems reporting use


India, North Africa, Mexico


Egypt, Mexico


Africa, Mexico, Trinidad


United States, Mexico


Colombia, Peru, Mexico


China, Mexico


North and Central America


United States, Mexico and Central America


Homeopathy, Mexico


United States, Mexico and Central America


Ayurveda, Yunani, Mexico


East and SE Asia, Central America


Homeopathy, North America, Mexico


Africa, Mexico


Ayurveda, Mexico


Homeopathy, Ayurveda,


Bengal, Japan, United States, Mexico

With respect to treatment, it has now been amply demonstrated that in many cases the pharmacological properties of herbal formulary specifically treat signs, symptoms, and/or probable pathogens. Table 4 lists some of the documented pharmacological properties of some genera used by the Highland Maya of Chiapas, Mexico, to treat diarrhea. A growing body of evidence demonstrates that folk systems are logical systems with significant empirical explanatory and predictive value. We have discovered that there are other healing systems built on distinct empirical/theoretical foundations that have high predictive power. Furthermore, the same genus, if not species, may be used in geographically dispersed and culturally distinct regions. Table 5 illustrates examples of the wide distribution of a small set of medicinal plants used for the treatment of diarrhea by the Maya of highland Chiapas, Mexico.2 This wide distribution is no doubt due in part to the commonality of these genera in local environments and over a wide geographic range. However, it is also dependent on some general selective process employed by humans (and, indeed, other primates), and based on principles that have yet to be clearly defined.

Diarrheal Disease Information Sites

International Life Sciences Institute (1998). News, 16(5).

The National Biotechnology Information Facility / Regents of New Mexico State University.

Foodborne Diseases Active Surveillance Network (FoodNet).

WHO (World Health Organization). Division of Diarrhoeal and Acute

Respiratory Disease Control 1211 Geneva 27, Switzerland.


  1. 1.

    The term health problems is used here to avoid the illness and disease dichotomy. (1) Although the dichotomy is useful in some discussions, it treats the physiological experience (sickness) in a way that is not helpful in this discussion. (2) That dichotomy fails to recognize the difference between infection and disease. (3) Such a dichotomy seems to assume that a systems approach (i.e., one that incorporates the patient’s family, social, and physical environments) does not exist in biomedicine. (4) Many conditions that are neither illness nor disease are recognized health problems in ethnomedical systems (such as deformities and dysfunction). Ethnomedical systems also distinguish conditions that are health-related, but not necessarily problems, and certainly neither illness nor disease (such as menstruation).

  2. 2.

    This is intended neither as a representative sample nor as an exhaustive survey of the distribution of use. It is merely a demonstration of the fact that many plant genera are widely and probably independently used for the same conditions.


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