A very sensItive (at nanogram level) and specific method is described for the identification and determination of bufotenin, serotonin and 5-hydroxytryptophane. Its application to the biochemical study of Amanita reveals high bufotenin contents in A. citrina and A porphyria. A macrochemical test, that can be done with very minute pieces of mushroom, allows the specific characterization of these two amanitas. Biological experiment on mice, comparing the mushroom extract activity with that of a single dose of bufotenin, shows that the high rate of bufotenin in the mushroom is inactivated when given oraly.