Goitrogens are naturally occurring substances that interfere with the function of the thyroid gland. Goitrogens get their name from the term “goiter” which means the enlargement of the thyroid gland. If the thyroid gland has difficulty synthesizing thyroid hormone, it may enlarge to compensate for this inadequate hormone production. Goitrogens cause difficulty for the thyroid in making its hormone. The role of iodine deficiency as an environmental factor in the development of goiter is established. Goiter is usually the most obvious sign of iodine deficiency; however, brain damage, mental retardation, reproductive failure, and childhood mortality are more serious consequences. Iodine deficiency also affects the socioeconomic development of a community. However, there are observations that indicate the existence of factors other than iodine deficiency. Iodine deficiency does not always cause endemic goiter, and iodine supplementation does not always result in complete eradication of goiter. Moreover, there is epidemiological and experimental evidence that concomitant exposure to other naturally occurring antithyroid agents magnifies the severity of endemic goiter. The foods that have been associated with disrupted thyroid hormone production in humans are broadly classified into two categories: cyanogenic plant foods, and flavonoids containing plant foods. Observations reveal that a number of plant foods usually consumed by the people of several regions contain goitrogenic/antithyroidal substances that interfere with thyroid hormone synthesis, acting at different levels in the thyroid gland and causing goiter and associated iodine deficiency disorders.