This study reports on the acute toxic effects of Aloe barbadensis Miller (Aloe vera) juice as well as high doses of the antioxidants vitamin C, vitamin E and Trolox頨a water soluble vitamin E analogue) to the salt water crustacean Artemia franciscana. Aloe vera juice exposure resulted in acute toxicity, being capable of inducing mortality at dilutions as low as 4 % juice and having an LC50 at 24 h of 4.6 % ᠰ.3. 6% Aloe vera juice dilutions were capable of causing 100% mortality within 4 h of exposure to A. franciscana. All of the antioxidants tested were also toxic to A. franciscana when tested in high doses. Toxicity of the antioxidants at 24 h was in the following order of toxicity: vitamin C (LC50 203.1 姯ml ᠱ1.3) > Trolox頨LC50 = 283.3 姯ml ᠲ5.8) > vitamin E (only low toxicity was observed at 24 h with the tested concentrations). However, in lower doses vitamin E and Trolox頷ere non-toxic and could block the toxicity induced by Aloe vera juice. Vitamin E was more effective than Trolox頡t blocking Aloe vera juice induced toxicity. Treatment of A. franciscana with antioxidants prior to exposure to juice was significantly more effective than the simultaneous treatment of antioxidant and the toxin. These data suggest that the lethality induced by Aloe vera juice is due to oxidative stress which can be blocked by antioxidant addition.