To determine the effect of a nicorandil congener, SG-209 on the myometrium.Isolated strips of myometrium, from nine women who underwent hysterectomy, were made to contract with 55 mM KCl before and after incubation with three concentrations of SG-209 (1.5, 3.0 and 10 microM). The mean height of contraction and the area under the curve were analysed using a non-parametric test.At a 10 microM concentration, SG-209 significantly decreased the mean area under the curve from 10.8 to 2.5 cm2 (p<0.05).SG-209 significantly relaxes the human non-pregnant myometrium. Along with its congener, nicorandil, it may be useful in clinical conditions that require uterine relaxation.