You don't want to be an April fool -- or any kind of fool -- when it comes to your health. Yes, those old wives knew a thing or two, but they never went to medical school or conducted a scientific study. Are you sure you know the answers to the following?

1: Chewing gum takes seven years to pass through your digestive system.

____ True ____ False _____ Only Juicy Fruit

ANSWER: False. The gum component itself is pretty indigestible, but will "pass" in a mass and will not stick your insides together, either. This one probably got going when exasperated parents tired of buying more gum after half an hour because their kids had chomped, then swallowed, their allotment. Also, swallowing gum was seen as ignorant and lower class.

"My husband's mother told him he would grow a gum tree in his stomach!" Loraine Stern, MD, clinical pediatrics professor at UCLA, tells WebMD.

Incidentally, the desire to chew for chewing's sake is quite ancient. Our ancestors used to chap away at tree resin. Did you know that Santa Anna of Alamo fame first turned gum manufacturers onto the gum resin. He thought it would be a good substitute for rubber. It's OK to swallow the occasional watermelon seed, too, unless you suffer from intestinal inflammation. Doctors are pretty sure watermelon seeds do not grow into full-fledged watermelons.

2: Cutting salt intake can help your high blood pressure.

___ True ____ False _____ Pass the pretzels

ANSWER: True. Americans are not in love with the idea of a tossing the salty snacks and tend to ignore this advice. But in 1998, at the 13th International Interdisciplinary Conference on Hypertension in Blacks, researchers said that in blacks with high blood pressure who get higher amounts of salt in their diets, even a small decrease in salt can help regulate blood pressure.

Blacks are particularly prone to hypertension, but the advice goes for everyone.

Tossing the salt shaker is not the whole answer. That's because most of the salt we eat comes from processed foods -- such as deli meats and canned foods. The best advice is to change your taste for salt. Don't automatically salt before tasting. Use herbal seasonings and condiments to flavor your foods. Pretty soon, things will begin to taste too salty and you'll be on the right track.

3: Cracking your knuckles will cause arthritis in later life.

__ True ___ False ____ Maybe

ANSWER: False. Depending on your point of view, knuckle-popping sounds disgusting or cool. There is no evidence that cracking your knuckles inflames the joints and leads to arthritis. The cracking causes the bones to pull apart, forming a gas bubble and breaking the adhesive seal in the joint. Crack!

About a quarter of the people in the U.S. crack their knuckles and might begin to lose their grip a little. Constant cracking can weaken the fingers.

4: Staring at an eclipse can blind you.

____ True ____ False ____ Only if you're not wearing specially made sunglasses

ANSWER: True. Never view the sun directly with the naked eye or with any unfiltered optical device, such as binoculars or a telescope!.

As sunlight enters the eye, it can damage the light-sensitive nerve endings in the back of the eye -- known as the retina -- causing vision loss.

Total and partial eclipses can lead to serious damage if precautions are not taken to prevent blindness. This is why there are only a few safe ways to view an eclipse, such as with a referred image. Regular sunglasses, exposed film, and even a welder's helmet are not safe.

5: Staying out in the cold and wind will give you a cold.

___ True ___ False

ANSWER: False. Colds are caused by viruses, with enough variations to give you a choice of 200 versions of a cold (which is why you get them over and over again). Because viruses get into healthy cells, it's difficult to kill them without knocking off the good cells. This is the job of your immune system, which usually clears out cold viruses in a week or two.

You can get the virus through inhaling infected air droplets sneezed or coughed by an infected person, or by touching something that an infected person has touched and then transferring the germs to your mouth or nose. You don't get it from cold air, slush, wind, or other wintry conditions. Cold viruses are more active in the winter, and that's why people get more colds in the winter.

Stern says she used to come home from swim class, her wet hair frozen crispy, but never got sick until her mother saw it and said, "You will get such a cold!" So what's the best way to ward off this miserable virus? Wash your hands often.

6: You can catch a sexually transmitted disease (STD) from a toilet seat.

___ True ___ False ___ Who told you that?

ANSWER: False. Mary J. O'Sullivan, MD, vice chair for OB-GYN at the University of Miami, tells WebMD that the idea that you could get an STD from a toilet seat "sounds believable," but is highly unlikely. Hard surfaces such as toilet seats are not conducive to STDs.

Incidentally, there is rumor that the toilet seat myth got started by men who wanted their wives to think a public restroom, not their mates' adulterous ways, had given them an STD.

7: Feeding kids sugar causes hyperactivity.

___True ___ False ___ Possibly

ANSWER: False. Don't go by the kids cake icing, advises O'Sullivan. You may notice a correlation between sugar intake and romping or grumping in the short-term, but not as a cause of chronic hyperactivity.

8: Drinking warm milk puts you to sleep.

___ True ___False ___ ZZZZZZZZZ

ANSWER: True, Stern says. Milk contains a chemical known as tryptophan. However, some foods, such as cheddar, avocados, some imported beers, and bologna or salami, can keep you awake.

Other sleep tips include never oversleeping. Get up about the same time everyday even if you had trouble sleeping. And try to get to bed at around the same time every evening.

9: Chocolate causes acne.

___ True ____ False ___ Who cares, it tastes good!

ANSWER: False. Stern says the link between chocolate intake and acne outbreaks has been broken. Another study, however, showed that stress can cause outbreaks.

Acne forms when the oil glands make too much sebum, a waxy substance that along with dead skin cells can clog pores. Bacteria grow and irritate the blocked pore given the red and swollen look to them. Too much harsh washing can further inflame the area. Doctors have many tools to attack and control acne these days. Some birth control pills even promise to improve acne.

10: Teething causes a fever.

___ True ____ False ____ Look for another cause.

ANSWER: False. Stern says studies have shown that symptoms such as fever and diarrhea may make teething babies more miserable but have not been triggered by the teething. "No correlation with tooth eruption," she says.

In fact, she adds, if the teething baby has a fever, you might want to look for another cause in addition to adding choppers.

Feel smarter? Those old wives over there are looking pretty smug.

Links:

Many Americans Believe Cancer Myths

Myths, Dos and Don’ts for a Healthy Pregnancy

Myths About Breastfeeding

National Stereotypes Miss the Mark

Visit WebMD's Health Center

By Jean Lawrence, reviewed By Louise Chang, MD

SOURCES: Loraine Stern, MD, clinical professor of pediatrics professor, UCLA. Mary J. O'Sullivan, MD, vice chair, ob-gyn, University of Miami. Snopes.com web site. Nutrition Farm web site. Indiana University. "The Real Truth About Health Myths," Better Homes & Gardens, January 1998. The University of Arkansas.