Diet Coke is the best-selling sugar-free soft drink in most countries in the word but rumors and curiosity abound about the drink’s health effects, some blatantly false and some surprisingly true. Can you separate fact from urban legend?

1. People have grown deathly ill from drinking cans of Diet Coke with dirty tops.

Myth. Legend has it that the lethal hantavirus spreads to humans when they drink soda contaminated by the droppings of warehouse rats or mice. True, humans can catch hantavirus from rodent waste bur there are no known cases of a person getting it from unclean Diet Coke cans (or any food packaging). Still, it’s a good idea to wipe icky stuff off your top before popping it.

2. Diet Coke is 99% water.

Fact. One Diet Coke ad actually brags about this. The marketing strategy behind the ad hinges on the idea that anything that is mostly water can’t be bad for you. (Not true. Insecticides are often mostly water.) What’s important is what makes up that other 1%.

3. Diet Coke’s sweetener was developed as an ant poison and is therefore hazardous.

Myth. Aspartame, the artificial sweetener in Diet Coke, was created by a chemist working on an ulcer drug. The compound doesn’t kill ants or short-circuit their nervous systems, as legend has it. Even if those things were true, they wouldn’t prove that aspartame is dangerous to humans, since many products that aren’t toxic to us (like black pepper) repel ants.

4. Diet Coke exacerbates arthritis.

Myth. In fact, the aspartame in Diet Coke may actually ease arthritis! Studies of people with osteoarthritis or a mix of rheumatoid and osteoarthritis found that aspartame relieved their pain and helped their joints move more fluidly. (Note: The studies weren’t done specifically with Diet Coke.)

5. Drinking Diet Coke while eating Mentos candies can create a mildly explosive reaction in your body.

This is a known fact though you can’t consume enough to cause a major internal eruption, yet some very sticky people have had a wild and crazy time creating geysers that shoot over 10 feet high, including a mini-version of the Las Vegas Bellagio fountains that involved hundreds of candies and 200 liters of Diet Coke.

How does it work? Certain types of Mentos have a microscopically rough surface that, when combined with the carbon dioxide in Diet Coke (or any soda), seems to create an insane number of bubbles. Pressure builds FAST and boom! Watch it happen.

6. Drinking Diet Coke can cause or worsen multiple sclerosis symptoms.

Myth. The Multiple Sclerosis Foundation has debunked this falsehood, as have the FDA and other organizations. The notion that Diet Coke can cause neurological disorders may be based on an observation by the Centers for Disease Control years ago, that in some people, aspartame seemed linked to mild neurological problems, such as headaches and moodiness. However, the CDC found that these symptoms are mild and affect most people, not just diet soda drinkers.

7. Diet Coke isn’t 0 calorie.

Myth. Contrary to Web rumors, Diet Coke does not have 40 or more calories, and the company does not get to call its drink calorie-free in exchange for paying big ol’ fines to the FDA. Drinks can only be called “calorie-free” if they have fewer than 5; Diet Coke has less than 1.

8. Diet Coke may cause cancer.

A big maybe. Arguments about an aspartame-cancer connection have flared for years. Recently, Italian researchers concluded that aspartame does increase certain cancers in rats, including breast cancer. But the scientific truism applies: Rats aren't people. And more than 200 studies, including one on humans in 2006 by the National Cancer Institute, have found no evidence of this. Still, suspicious groups remain, including the Center for Science in the Public Interest, an ardent consumer advocacy group. What to do?

Drink responsibly and we don't mean taking the FDA's "acceptable" max of 21 cans of aspartame-sweetened soda a day for a 165-pound adult although research says there's an informal consensus that, for adults, a can a day is likely to do no harm.

Tons of cola drinkers have switched to diet formulas to slash their sugar intake. And avoiding foods with simple sugars as one of their first five ingredients can make your RealAge 3.6 years younger. Sweet!

True that!