Questionnaires answered by 99 student nurses concerning bladder responses to laughter showed that roughly 25% had experienced such reactions at some time in their lives and about 10% could still register such phenomena at the end of their second decade. Giggle incontinence is not a condition confined to an "all or nothing" response of complete micturition. The evidence seems to indicate that the condition is due to some inborn and quite ordinary trigger mechanism exposed by physiological variations in sensitivity or specific control.