The deodorizing activity against methanethiol (CH₃SH) of compounds from Houttuynia cordata Thunb, “dokudami" in Japanese, were identified. The main deodorizing compound was isolated from the methanol extract of the dried aerial parts of H. cordata as caffeic acid. This is the first report to identify caffeic acid as the deodorant against CH₃SH in H. cordata, although caffeic acid is an established compound. The reaction products of caffeic acid and CH₃SNa were chromatographed, and three peaks were separated as the conjugates. Their structures were determined by MS and NMR methods to be those of 2-methylthiocaffeic acid, 5-methylthiocaffeic acid and 2, 5-dimethylthiocaffeic acid.