The occurrence of tryptamine derivatives and urea in Panaeolus cyanescens, also known as Copelandia cyanescens, from Australia, Hawaii and Thailand was investigated. All 70 collections contained psilocin, serotonin and urea. Those from Hawaii were also relatively rich in psilocybin, whereas the species from Australia and Thailand were virtually exempt of this compound. Many collections also contained detectable amounts of precursors as tryptophan, tryptamine and baeocystin, but 5-hydroxytryptophan — widely encountered in many other Panaeoloideae — was found to be absent in all samples. The role of these 4- and 5-hydroxylated tryptamine derivatives in the metabolism of the fungus and their possible chemotaxonomic significance is briefly discussed. Volunteers ingesting samples of Panaeolus cyanescens reported a stronger psychotropic effect than that experienced with the same amount of Psilocybe semilanceata.