Propylthiouracil is a thiourea anti-thyroid drug and is often used in clinical practice. The main effect is to inhibit the synthesis of thyroid hormone, but not the release of already synthesized thyroid hormone. Propylthiouracil is a short-acting antithyroid drug. The dosage of propylthiouracil is adjusted according to the results of thyroid function monitoring. Because of its relatively short duration of action, propylthioxypyrimethamine is also used clinically in the resuscitation of patients with hyperthyroidism. The most common side effect of propylthioxypyrimethamine drugs is a tendency to cause toxic liver disease, and a significant increase in transaminases will be found in such patients. If there are liver function abnormalities, liver-protective drugs should be added or propylthiouracil should be discontinued promptly.