This study demonstrates that Ispaghula has a gut-stimulatory effect, mediated partially by muscarinic and 5-HT(4) receptor activation, which may complement the laxative effect of its fiber content, and a gut-inhibitory activity possibly mediated by blockade of Ca(2+) channels and activation of NO-cyclic guanosine monophosphate pathways. This may explain its medicinal use in diarrhea. It is, perhaps, also intended by nature to offset an excessive stimulant effect.