Toxicological Reviews

, Volume 23, Issue 2, pp 65–73 | Cite as

Poisoning Due to Chlorophenoxy Herbicides

  • Sally M. Bradberry
  • Alex T. Proudfoot
  • J. Allister Vale
Review Article


Chlorophenoxy herbicides are used widely for the control of broad-leaved weeds. They exhibit a variety of mechanisms of toxicity including dose-dependent cell membrane damage, uncoupling of oxidative phosphorylation and disruption of acetylcoenzyme A metabolism. Following ingestion, vomiting, abdominal pain, diarrhoea and, occasionally, gastrointestinal haemorrhage are early effects. Hypotension, which is common, is due predominantly to intravascular volume loss, although vasodilation and direct myocardial toxicity may also contribute. Coma, hypertonia, hyperreflexia, ataxia, nystagmus, miosis, hallucinations, convulsions, fasciculation and paralysis may then ensue. Hypoventilation is commonly secondary to CNS depression, but respiratory muscle weakness is a factor in the development of respiratory failure in some patients. Myopathic symptoms including limb muscle weakness, loss of tendon reflexes, myotonia and increased creatine kinase activity have been observed. Metabolic acidosis, rhabdomyolysis, renal failure, increased aminotransferase activities, pyrexia and hyperventilation have been reported. Substantial dermal exposure to 2,4-dichlorophenoxy acetic acid (2,4-D) has led occasionally to systemic features including mild gastrointestinal irritation and progressive mixed sensorimotor peripheral neuropathy. Mild, transient gastrointestinal and peripheral neuromuscular symptoms have occurred after occupational inhalation exposure.

In addition to supportive care, urine alkalinization with high-flow urine output will enhance herbicide elimination and should be considered in all seriously poisoned patients. Haemodialysis produces similar herbicide clearances to urine alkalinization without the need for urine pH manipulation and the administration of substantial amounts of intravenous fluid in an already compromised patient.


Soft Tissue Sarcoma Standardise Mortality Ratio Standardise Incidence Ratio Dermal Exposure Urine Alkalinization 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The authors are grateful to Professor Peter Eyer for his helpful advice. The authors received no funding in the preparation of this manuscript and do not have any conflicts of interest relevant to its contents.


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Copyright information

© Adis Data Information BV 2004

Authors and Affiliations

  • Sally M. Bradberry
    • 1
  • Alex T. Proudfoot
    • 1
  • J. Allister Vale
    • 1
  1. 1.National Poisons Information Service (Birmingham Centre) and West Midlands Poisons UnitCity HospitalBirminghamUK

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