What's Growing in Your Medicine Cabinet?

Nov. 5, 2005 — -- You might keep your bathroom immaculately clean -- with gleaming tiles and perfectly clear mirrors. But the greatest source of bacteria and illness may lie somewhere that you're forgetting: inside your medicine cabinet.

Expired medications, old cosmetics and toothbrushes past their prime can make you sick. "Good Morning America" talked to the experts to find out what is the shelf life of different items typically found in medicine cabinets.

If you go through all the medicine bottles in your medicine cabinet, you are bound to find some that have expired. And, when you locate these, it's something to take seriously, according to Dr. Evelyn Hermes-DeSantis, clinical associate professor of pharmacy at Ernest Mario School of Pharmacy at Rutgers University in Piscataway, N.J.

"You always have to worry about contamination with that," she said.

A drug's expiration date is the point at which it has lost 10 percent of its potency.

"With some drugs, 90 percent is still good enough," Hermes-DeSantis said. "Some drugs, it's not."

So, an expired drug might not work, but it's unlikely to hurt you. There are, however, some notable exceptions such as an antibiotic known as tetracycline, which can actually degrade into something harmful, said Hermes-DeSantis.

She also recommends throwing out expired bottles of oil capsules (such as fish oil supplements) because they can become rancid.

Unlike with medication, makeup manufacturers are not required to put expiration dates on their products. Shelf life can vary dramatically depending on how many preservatives are in that lipstick or powder. Most makeup products should be thrown away after a year or two. By then, the anti-microbial preservatives have dissipated, said Dr. Elizabeth Brooks, assistant professor of biology at Rowan University in Glassboro, N.J.

"The whole purpose of makeup is to look better," Brooks said. "And so if we are introducing bacteria-loaded makeup onto our skin, we're increasing the risk for acne."

You could also get something much worse -- a staph infection, she added.

Powder-based products hold up longer than liquids, but mascara has the shortest shelf life.

"Two months is when we should throw out our mascara, because we could contract bacterial conjunctivitis and that's actually relatively common," Brooks said.

If you allow your kids to use your makeup to play dress up, routinely scrape off the top layer, Brooks said.

"I tell my girls, 'don't share makeup with your friends.' If they have to because they feel pressure, give their friend the makeup and I'll buy you a new one," she added.

Brooks recommends dunking toothbrushes in hydrogen peroxide from time to time and buying new ones every few months.

Razor blades should be replaced even more frequently, she added. Also, they should be kept outside the shower if possible to prevent the growth of staph bacteria.

"When you're shaving, you're making abrasions to your skin," Brooks said. "So now all that bacteria or fungi have a route of entry into your body."