Picrotoxin is a toxin obtained from the seeds of the shrub Anamirta cocculus and used as a central nervous system stimulant, antidote, convulsant, and non-competitive antagonist at GABAA receptors. Picrotoxin has been used as a CNS stimulant and an antidote in poisoning by CNS depressants, especially barbiturates also used for the treatment of respiratory distress. Exposure to picrotoxin causes eye and skin irritation, respiratory and digestive tract irritation and CNS effects. Despite its potential toxicity to mammals in large enough doses, picrotoxin is also sometimes used as a performance enhancer in horses.