Catechu is the non-mutagenic component of betel quid. We have tested catechu extract and catechin for anti-mutagenic activity in Salmonella typhimurium strain TA98 against environmental mutagens relevant to India. Catechu extract, as well as catechin, shows a dose-dependent decrease in the mutagenicity of tobacco and masheri extracts, and bidi and cigarette smoke condensates in TA98 with S9 mix. Mutagenicity of extracts of charred and non-charred meat in TA98 is also inhibited by catechu extract and catechin in a dose-dependent manner with or without S9 mix.