Carminative activities of 34 alcohols, esters, ethers, phenols, and carbonyl compounds were determined using the guinea pig isolated ileum preparation and are expressed as the ability to produce a 50% inhibition (ID50) of a standard response to carbachol. Aqueous solubilities were measured at 37 degrees using either UV absorption or GLC. The ratios of solubility to ID50 were reasonably constant, suggesting nonspecific biological activity, similar to that previously observed with general anesthetics. Hansch analysis indicated that carminative activities were largely controlled by solubility, as indicated by octanol-water distribution coefficients. The principal remaining factor appeared to be the steric availability of the oxygen atom in the functional group of the compound.