Recent studies have demonstrated that orocaecal transit time is prolonged both in the luteal phase of the ovulatory cycle in normal women and during pregnancy, but have made no attempt to differentiate between the individual effects of gastric emptying and small intestinal transit. We have assessed the effect of the normal menstrual cycle on gastric emptying of solids and liquids in 10 women, using a dual isotope scintigraphic technique. In each subject gastric emptying was measured on 2 days: first during the follicular phase (day 8-10) and then during the luteal phase (day 18-20) of one ovulatory menstrual cycle (where day 1 was the first day of menstrual bleeding). Measures of solid and liquid gastric emptying did not change significantly between the follicular and luteal phases indicating that the normal menstrual cycle has no effect on gastric emptying.