Are regular exterminators safe, or should I pay extra for the "green" companies?

Pesticides are designed to kill. These chemicals almost always pose small risks to humans; some are suspected carcinogens, while others are linked to skin and eye irritation. So the short answer is that you should opt for the least toxic pest control possible that will still solve your critter problem. It is important to get rid of the pests because they can contribute to health issues like allergies and asthma.

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A reliable exterminator (find one in the National Pest Management Association's database, and make sure he has experience with your particular bug) should be able to explain what method he would use in your situation and why. For some pests, there may not be an effective green treatment at all; for others, nonchemical tactics may actually work as well as or better than synthetic insecticides. You can look up fact sheets and other info on specific pesticides online via the National Pesticide Information Center or the Environmental Protection Agency in order to make an informed decision.

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And use common sense: Yes, a method like boric acid is generally less toxic than, say, organophosphates, which work by disrupting the bugs' nervous system—and can affect yours as well. But no matter what type of pest control you're using, it's smart to limit your exposure. Follow the exterminator's instructions carefully, clear the area of toys and food beforehand and keep children and pets away during treatment.

Health's medical editor, Roshini Rajapaksa, MD, is assistant professor of medicine at the NYU School of Medicine.