Bed-wetting, or enuresis, is involuntary urination that usually occurs during sleep. It is common in children up to age 5, and about 15 percent of older children aged 5 to 13 also have bed-wetting episodes. The precise cause is unknown, but it may be due to delayed development of bladder capacity, constipation, or diseases, such as urinary tract infection, kidney disease, or diabetes mellitus. Emotionally stressful events, such as hospitalization or loss of a parent, may contribute to enuresis. In most cases children outgrow the problem, but persistent cases require a physical examination in case there is an underlying medical problem. Enuresis not caused by a physical problem can be halted with effective behavior-modification therapies.

Another technique uses a battery-operated urinary alarm that is set off by wetting; eventually the child learns to waken before the alarm. In rare cases the drug imipramine is prescribed. Bibliography: Wexford, Heather, Toilet Training and Bed Wetting (1988).