A rapid method for the determination of skatole (3-methylindole) in faeces by reversed-phase high-performance liquid chromatography is described. Samples of 0.5 g were extracted with 2 ml of methanol. The extract was purified on Amberlite XAD-8. The lower limit of detection was 2.5 ng per injection (0.2 microgram/g faeces). The mean recovery of skatole was 95%, and the mean coefficients of variation were 7.0% (intra-assay) and 11.8% (inter-assay). Skatole concentrations were clearly lower in faeces from ruminants (average 2.6 micrograms/g for goat, sheep and cattle) than in those from monogastrics. Mean concentrations in human samples were 15.5 micrograms/g, and 10 micrograms/g in mature domestic pigs. An effect of the anabolic status on skatole concentrations in faeces of pigs is likely.