Every day we're exposed to a multitude of man-made chemicals in the food we eat, the air we breathe and the products we clean our homes and wash our bodies with. For some people, like journalist Jane Little, the burden can be almost too much to bear. Certain chemicals trigger extreme physical reactions, leaving her ill and exhausted for days at a time. It's a debilitating condition for her and many thousands of fellow sufferers. Some estimates suggest that 15% of the American population believe they experience ill effects from domestic chemicals.