Food may contain different chemicals, both natural and man-made. The number of combinations is infinite and the sources many: food, medicines or consumer goods like cosmetics. But exposure to multiple chemicals is not harmful under normal levels of exposure. High margins of safety used in current regulatory systems address potential cumulative effects from substances with similar modes of action (i.e., those that act via the same key biological changes). Find out how risks posed by multiple chemicals are assessed from a European Food Safety Authority scientist.