Goitrogens are substances that disrupt the production of thyroid hormones. This triggers the pituitary to release thyroid-stimulating hormone (TSH), which then promotes the growth of thyroid tissue, eventually leading to goiter.

Chemicals that have been shown to have goitrogenic effects include:

Foods which have been demonstrated to have goitrogenic effects include soy, cassava (when crushed and not detoxified by soaking,) vegetables in the genus Brassica (such as broccoli and cabbage),^{[page needed]} and other cruciferous vegetables. In places where iodine deficiency exists in tandem with millet being a major component of the diet, millet consumption can contribute to thyroid enlargement which is the start of endemic goiter.