Anatoxin-a (AN) and homoanatoxin (HMAN) are two powerful nicotinic agonists. Symptoms of AN and HMAN toxicosis include tremors, convulsions, muscle fasciculations, and rapid death due to respiratory failure. AN is unstable under natural conditions and is naturally degraded either partially or totally to the nontoxic products dihydroanatoxin-a and epoxyanatoxin-a, depending on environmental conditions. Animal bioassays, in particular the mouse bioassay, have been applied to the detection of the ANs in samples and extracts. Methods are currently being refined to synthesize an analogue of AN for monoclonal antibody production that could be incorporated into a bioassay kit for detecting AN. The dihydro- and epoxy-degradation products of AN and HMAN do not possess the unsaturated ketone chromophore in their structures so cannot be detected by ultraviolet methods. The biosynthetic pathways of AN and HMAN have been studied by feeding experiments using radiolabeled precursors.