AIM: This in vitro study was to evaluate the endogenous pH, titratable acidity, total soluble solids content (TSSC) and nonreducing sugars of energy drinks. METHODS: Nine energy drinks (Bad Boy Power Drink, Red Bull, Red Bull Sugar Free, Flying Horse, Burn, Night Power, Flash Power, Flying Horse Light and 220V) were evaluated by a randomised experiment with 3 repetitions on each sample. pH analysis performed by potentiometry and buffering capacity was assessed by dilution of each drink. Increments of 0.1 N KOH were titrated until neutrality reached. TSSC readings were performed by Brix refractometry using an Abbé refractometer. RESULTS: pH values ranged from 1.52 (Flash Power) to 3.20 (Red Bull) and all drinks showed pH 5.5. Titratable acidity values ranged from 0.56 (220V) to 1.04 (Bad Boy Power Drink). Flying Horse Light presented the lowest TSSC content (1.66%) and Flying Horse presented the highest (12.58%). Non-reducing sugars values ranged from 0.00% (Red Bull Sugar Free and Flying Horse Light) to 54.33% (Flying Horse). CONCLUSION: The energy drinks evaluated have a high erosive potential, as they present low pH and a high non-reducing sugar content.