Is it OK to take Advil PM or Tylenol PM most nights to help me sleep? —C.O., by e-mail

Probably not. The snooze-inducing ingredient in those pills is the antihistamine diphenhydramine, also found in Benadryl and many over-the-counter sleep aids. Alone, that ingredient can worsen asthma and cause next-day drowsiness. Long-term use can lead to rebound insomnia and dependency. And since the pills include a painkiller, you might suffer other side effects, such as stomach irritation from ibuprofen, in the Advil product, and liver damage from acetaminophen in the Tylenol one. Consider slowly weaning yourself off the pills. And try “sleep hygiene” steps such as avoiding alcohol and caffeine before bed, and exercising during the day. A white-noise machine may help by drowning out distracting sounds. If problems persist, talk with your doctor about the occasional use of a prescription sleep aid.

Read our recent survey on the nation's sleeping habits, take our interactive sleep quiz, read our FREE Best Buy Drugs report on sedatives, and find out what treatments work best for insomnia in our Treatment Ratings (subscribers only).