Toxicity, Mutagenicity and Carcinogenicity Report 1996 Toxicity Hydrazine Derivatives Naturally occurring hydrazines, such as agaritine, are found in edible mushrooms, and the Committee were informed that human consumption of the commercially grown edible mushroom Agaricus bisporus is increasing. The Committee was advised by the COC and COM that the chemical structure of agaritine and its putative metabolites (N acetyl 4 (hydroxymethyl) phenylhydrazine and 4 (hydroxymethyl) benzene diazonium ion) give rise to concern about mutagenic and carcinogenic potential, a concern strengthened by the activity of agaritine in bacterial mutation assays. The data concerning the mutagenic potential of agaritine in mammalian cells in vivo and in vitro are limited and insufficient to allow any firm conclusions to be reached. The stabilised forms of the putative metabolites of agaritine showed evidence of carcinogenicity in long term testing in Swiss mice, although the studies were of unusual design. N-acetyl-4-(hydroxymethyl)phenylhydrazine induced an increased incidence of tumours of the lung and blood vessels; 4-(hydroxymethyl)benzene diazonium ion tetrafluoroborate induced an increase in glandular stomach adenocarcinomas. There was evidence that agaritine itself was carcinogenic in laboratory animals, but further testing would be necessary to confirm this.   The Committee agreed with the concerns of the COC and COM that the structure and mutagenic potential of agaritine suggested that future research was needed. In order to proceed with this assessment, information on absorption, distribution, metabolism and possible detoxification of this compound by mammals was needed. The data available indicate that there are other toxins present in A. bisporus and that toxic effects in laboratory animals fed mushrooms cannot be directly attributed to agaritine. The Committee recommended that more knowledge was required on the nature, bioavailability, and toxicology, including mutagenic potential, of the other toxins present in A. bisporus, before a definitive conclusion could be reached and welcome the research that MAFF was funding to address these questions. The Committee agreed with the COC and COM that the data currently available were not of sufficient concern to require the need for measures to reduce agaritine intake by the population.