Q. My 8-year-old still wets his bed. What can I do?

A. Bed-wetting is considered normal until age 6. If it continues beyond that, it should be treated because it can lead to family discord and low self-esteem.

An average 15 percent of kids are bed-wetters. A full 77 percent of children of parents who were both bed-wetters also wet their beds. Forty-four percent of children who have one parent who was a bed-wetter have the trait.

Bed-wetting is sometimes caused by constipation, urine infections or emotional stress.

Bed-wetters are deep sleepers. At bedtime, tell your son to try to get up to use the bathroom if he has to pee. Have him pretend to be asleep, then to awaken, walk to the toilet, then return to bed. Leave a night light on. A great picture book you can read with him is "Dry All Night."

Avoid diapers or pull-ups, which can hamper motivation for getting up at night. If your child wets the bed, have him or her shower in morning so there's no urine odor when they go to school. Don't tease or punish a child for wet nights because this will cause emotional problems — no child likes being wet.

It is unknown whether getting kids to go to the toilet repeatedly and to change their own wet sheets really works. And while drug treatment stops bed-wetting, when the treatment stops, the habit resumes.

At age 7, kids may be ready for something we know works — a bed-wetting alarm, which has the highest cure rate of any treatment. But the child must want the alarm, which senses urine and sounds loudly or vibrates.

In the beginning, a parent needs to help wake the child, escort him or her to the toilet and back to bed with the alarm reset. Kids will learn to wake up earlier and earlier during bed-wetting episodes.

Few children awaken easily in the first few weeks of alarm use, so they'll need the help of their parents. Without parental help, alarm treatments are doomed to failure.

And don't give up too soon — there's little improvement the first month, but by four to six months, 75 percent of bed-wetters are cured. Relapses may require retreatment.

Alarms also work in teens.

If you already tried an alarm and it did not work, it may be worth trying it again — with a different alarm.

Those that only vibrate won't wake most bed-wetters and won't alert the parents to help awaken the child. Some alarms, such as the Malem Ultimate, combine sound and vibration.

As www.bedwettingstore.com puts it, the average length of time to become dry varies from a few weeks to a few months, but treating bed-wetting with an alarm can reduce the time kids are affected by years. The Web site also sells waterproof mattress covers and books such as "Seven Steps to Nighttime Dryness."

Dr. Landis Lum is a family-practice physician for Kaiser Permanente and an associate clinical professor at the University of Hawai'i John A. Burns School of Medicine. Send your questions to Prescriptions, Island Life, The Advertiser, P.O. Box 3110, Honolulu, HI 96802; fax 535-8170; or write islandlife@honoluluadvertiser.com. This column is not intended to provide medical advice.