A urodynamic assessment with an anticholinergic test has been performed on 145 patients suffering of urge incontinence or micturition frequency. Eighty per cent had a detrusor instability and in those the test has shown to be positive in three half of the cases. In this group there was also an improvement with the oral treatment. In the others groups, the anticholinergic per os was almost never usefull. Anticholinergic drugs (not always well tolerated) are usefull when there is an instability and when the test is positive but not in the other cases.