[Toxicologic evaluation of nitrofuran derivatives].

The most important side effects of numerous nitrofuran derivatives are their mutagenicity and carcinogenicity. They are due to metabolites of this group of substances in the microbial and animal metabolism. The mutagenic or carcinogenic metabolites are either excreted or covalently bound in the animal organism and may then form persistent residues in the slaughtered animal. If active at all, such residues are toxicologically less active than free metabolites. To determine their bioavailability and to exclude any risk to the consumer, their relay-toxicity should be tested using suitable experimental animals.