The stress of thinking you're going to be poisoned by chemicals can cause more damage than the actual exposure to the chemicals.

It's called "Chemophobia", and medical experts says it's exemplified by too much concern, for example, about using and heating plastic containers.

Dr. Jack Bend of the Schulich School of Medicine says our exposure to toxins and carcinogens in plastic food and beverage containers is nothing compared to second hand smoke.

He points out people make the false assumption that chemicals which in very high concentrations can cause cancer will also cause it in low concentrations.

Black pepper, for example, contains the carcinogen " Isosaphrol", but people aren't at risk sprinkling pepper on their food because the dose of the cancer causing agent is so low.

It's the same, he says, with plastics.

So, an old plastic container can be a hazard, but only because of little chunks of plastic that can come off, not because of the chemicals in it.

Dr. Bend says putting plastic containers in the microwave is a minimal risk at most, because the chemicals leaching out of them are so miniscule...