Dr. Ken, I caught my boyfriend not washing his hands when he was in the bathroom, and he acted like it was no big deal. But I think it's disgusting. Can you explain to him how messed up his filthiness is?

-- Angela P.

Angela, Your boyfriend isn't the only slovenly one.

A recent study of hand-washing habits found that among the 6,000 people observed, nearly all the women washed their hands, yet only 66 percent of men did.

Read all of Dr. Ken's response (after the jump).

Failing to be a hand washer means your man is putting himself, you and anyone who's in contact with him, at risk of infection. Every time you shake hands with a non-washer, pick up or hold an object just held by a non-washer, or touch something just touched by a non-washer, you take a chance of infecting yourself with any number of cold-causing viruses or the flu. Bacteria can also be picked up or transmitted this way.

Here are specific tips to keep in mind (some of which may nurture your inner OCD):

1. Wash your hands regularly: Before you eat; before and after preparing food; when you get home from work or after errands; after you cough or sneeze; after using the bathroom; after touching surfaces or objects in public areas.

2. Wash well: Washing hands means using soap, lathering up for at least 20 seconds and rinsing under running water. Get between your fingers and your nails. Dry with a paper towel, and it's not a bad idea to use a paper towel to turn off the sink and even open the door, particularly in public bathrooms.

3. Don't touch your face: Touching your hands to your mouth or nose, particularly, is like offering germs some food and a warm bed. If you need to pick, wash your hands first (and, for our sake, after).

4. Hand washing versus hand sanitizers: Overall, hand-washing is probably better, but hand sanitizers are very effective and are less likely to irritate the skin than frequent washing. Hand sanitizers must have at least 60 percent alcohol content to be effective.

5. Antibacterial soap versus regular soap: Don't get me started on what is, at this point, just a marketing effort by the soap lobby. Neither colds nor flu are caused by bacteria, so "antibacterial" is not relevant. Second, plain old everyday soap is just as effective for keeping you germ-free as antibacterial soap. No matter what type of soap you use, it keeps you clean only if you wash properly (re-read 2 above).

UPDATE: Dr. Ken has responded to the enormous amount of comments and questions he's received about hand-washing:

More Reasons Men Should Wash

Another article by Dr. Ken: Did you know that cell phones may be affecting your sperm count?

Cell Phones Are Ringing Your Boys


Dr. Ken Spaeth is a physician and Research Fellow at the Harvard School of Public Health. He is also co-author of the Bioterrorism Sourcebook. You can e-mail him your questions at askdrken@aol.com.