In a randomised double-blind cross-over trial of 19 females with motor urge incontinence but without bladder suspension defect, the effects of 14 days' treatment with emepronium bromide 200 mg qid, flavoxate chloride 200 mg qid or placebo qid were compared by means of micturition charts, the patients' drug preferences and evaluation of side effects. Placebo was the only drug giving rise to a statistically significant decrease in the frequency of voidings, incontinence and nocturia. Forty-seven per cent of the patients preferred placebo and side effects were less frequent during treatment with this medication. No differences could be demonstrated between the effects of emepronium bromide and flavoxate chloride. Perhaps detrusor instability is not always the main reason for the voiding dysfunction in these patients, in whom the effect of placebo was equal or superior to the effect of "active drugs" and superior to no treatment at all.