This review will focus on those drugs that produce fallacious TFTs, in the absence of any clinically relevant effect on thyroid hormone secretion. Many of the medications actually affect thyroid functioning and cause hypothyroidism, thyrotoxicosis, thyroiditis, etc. Those drugs have not been discussed in this review. Awareness about these drug-induced TFT alterations could avert misdiagnosis and overtreatment of euthyroid subjects.