It would appear that muscimol is the psychoactive constituent, and that following ingestion of ibotenic acid, a fraction of the material decarboxylates to muscimol, which then produces the inebriation. After oral ingestion of ibotenic acid, a substantial percentage of the drug is excreted unaltered in the urine, but small amounts of muscimol are also excreted (Chilton, unpublished). This mechanism would potentially explain the Siberian urinary drug-recycling practice. After ingestion of the mushroom, the celebrant would excrete substantial amounts of ibotenic acid in her or his urine. A second user ingesting the urine of the first, would cause some of the ibotenic acid again to be decarboxylated to muscimol during digestion, producing inebriation when that muscimol was absorbed; and the bulk of the ibotenic acid would in turn be re-excreted in her or his urine. Thus a 100 mg dose of ibotenic acid might potentially represent four or five 10-15 mg doses of muscimol and Steller's 1774 report that one dose of mushrooms could be recycled through four or five individuals is certainly feasible. Muscimol itself probably does not play a significant role in urinary drug recycling, since it was found that only a small percentage of injected muscimol was excreted in the urine of mice (Ott et al 1975A). This hypothesis has yet to be verified quantitatively in human beings, though it has been demonstrated qualitatively in preliminary experiments (Chilton 1979).