For countless centuries, many fishermen in South and Southeast Asia used a stupefying fish poison derived from the seeds of the fishberry shrub (Anamirta cocculus). Picrotoxin, the active ingredient of fishberry seeds, acts as a noncompetitive GABAA receptor antagonist. A neurostimulant and occasional convulsant, picrotoxin can block chloride conductance enhanced by GABAA receptor agonists such as propofol and barbiturates. Thus, picrotoxin has been employed to investigate anesthetic mechanisms of action at the GABAA receptor, as well as used as an antidote for barbiturate toxicity. Manufactured by Merck in Germany, the bottle of picrotoxin (above) is now part of the collection of the Wood Library-Museum.