The potential toxicants in food are derived from natural or industrial sources. Compounds like lectins and glycoalkaloids that are toxic to man are naturally present in some vegetables like potatoes or legumes. A wide variety of marine toxins mostly produced by dinoflagellates occurring secondarily in molluscs and mussels are usually ingested by human beings causing poisoning. On the other hand, toxic compounds find their way into food during manufacture, storage, or transportation. These include largely the industrial contaminants, persistent organic pollutants (POP), pesticides, heavy metals, and toxins of fungal and bacterial origin. Further, toxic compounds like higher alcohols may be produced as byproducts during processing. Migration of compounds from packaging materials into packaged food like contamination with lead from solder in certain metal cans is well known. Additives (emulsifiers, preservatives, and antioxidants) could also influence the quality of foods. Solvent residues may find their way into food as a result of their use in extraction processes like the use of trichloroethylene and methylene chloride in decaffeination of coffee. In addition, poor hygiene, storage, and preparation may also lead to food contamination by various microbes and ova or cysts of nematodes. The problem of food contamination can be overcome to a great extent by regular surveillance and monitoring programmes and strict implementation of food and adulteration act. In the present review some of these aspects of food contamination have been discussed in detail.