Like the rapacious Audrey II in "Little Shop of Horrors," some of the easiest-to-grow houseplants can devour what's bad for you. (But not bad boyfriends - or girlfriends!) Three bad-boy culprits that plants can filter out of your environment are benzene, formaldehyde, trichloroethylene. Benzene seeps out of paints, furniture wax, glues, and detergents, not to mention cigarette smoke. It stops bone marrow from making red blood cells and damages your immune system. Formaldehyde is a carcinogen that's in everything from carpeting to wrinkle-resistant clothing (you knew that was too good to be good for you!) and plywood to pressboard. Trichloroethylene is found in adhesives, rug cleaners, paint removers an,d strippers. It can cause respiratory problems and foster cancer.

So get out the potting soil! NASA discovered the most powerful plant filters (at least in closed chambers): English ivy took 90 percent of benzene and 10 percent of trichloroethylene out of the air; Gerbera daisies scrubbed 68 percent of benzene, 35 percent of trichloroethylene and 50 percent of formaldehyde; and varieties of dracaena sucked up all three chemicals.

Other important steps in keeping the air in your home healthy:

• Keep rooms well-ventilated so you don't hold in pollutants.

• Don't overwater plants. Mold can thrive in the potting soil - and that's an allergy trigger.

• Keep air filters in humidifiers, air conditioners, and central heating and cooling systems clean.

• Use a do-it-yourself test to check indoor radon levels: It's the No. 2 cause of lung cancer. If levels are high, have a specialist install a radon ventilation system.

© 2012 Michael Roizen, M.D. and Mehmet Oz, M.D.
Distributed by King Features Syndicate, Inc.