description of a slave who smelled like fish in The Tempest may indicate that the condition was recognized much eariier. It is difficult to estimate the true prevalence of this syndrome, but a decade ago there were more than 200 cases described, which was considered an underestimate at that time.5 More recently, it has been shown that undiagnosed cases of trimethylaminuria may be fairly common among patients suffering from idiopathic malodor production,6 which supports the thought that this disorder is under recognized. Genetic studies have estimated the incidence of heterozygous carriers to range from 0.5 to 11 percent depending on the ethnicity examined.7,8Cases have been reported from nearly all parts of the world and in both sexes,