When I was a kid, I would get very bad nosebleeds. If nothing else worked, my mother would get out her keys and drop them down the back of my neck. I wish I knew why it worked it so well.

We have heard from many people who have had success stopping nosebleeds with keys or a cold butter knife against the back of the neck. We don't know why this trick works, but one reader offered the following from his experience as a medic doing water rescue:

"The keys work because of the mammalian dive reflex. Cold hits the nerves in the neck, causing the blood vessels to constrict. You might notice your pulse slowing too.

"The dive reflex is why cold-water drowning victims are not usually pronounced dead until they are 'warm and dead.' Cold water only in the face/head area shunts blood to the organs and away from the skin and slows the metabolism for survival. The vital signs are often too weak to detect."







I have a history of sleeping problems. I just started taking half an acetaminophen PM tablet (one-fourth the adult dose) just before bed. This allows me to sleep through the night. Is this safe?

If pain is not an issue, you don't need the acetaminophen. The PM part of the pill is diphenhydramine (DPH). This is the antihistamine found in Benadryl, and it makes people drowsy. At the dose you are using, there should be few, if any, side effects.

Joe Graedon, a pharmacologist, and Teresa Graedon, an expert in medical anthropology and nutrition, can be reached at www.peoplespharmacy.com or care of this newspaper.