Twenty consecutive female patients with urge incontinence and stable detrusor function on provocative rapid fill CO2-cystometry were treated as out-patients with a bladder training programme and with terodiline/placebo in a double-blind cross-over design. Frequency and incontinence episodes decreased significantly, while first sensation and cystometric bladder capacity increased. Both objectively and subjectively terodiline was significantly better than placebo with 50% (95% confidence limits 18-82) more patients improved on terodiline than on placebo. Thirty percent of the patients (95% confidence limits 12-54) relapsed after withdrawal of terodiline. At 3 months follow-up the remaining 70% were satisfied with the outcome of the training programme. Side effects were mild and reversible. Serum creatinine and alkaline phosphatase increased slightly on terodiline and the diastolic blood pressure was probably also increased by terodiline. In conclusion, female patients with idiopathic urge incontinence and stable detrusor function did respond to treatment as do female patients with urge incontinence and proven instability.