Antithyroid drugs adverse effects are varied and rare. Autoimmune disorders (vasculitis, lupus erythematosus, polyarthritis...) are unusual and serious complications of antithyroid drugs. Since 1945, fewer than 100 cases of systemic manifestations related to antithyroid drugs have been reported in the literature, most frequently with propylthiouracil. The outcome is usually good after drug discontinuation, but some fatal cases have been reported. Because possible cross-sensitivity with other antithyroid drugs, the appropriate treatment for hyperthyroidism relapse if a patient has had an antithyroid drug adverse reaction, should be 131I-Iodine or surgery. We report four new cases of systemic manifestations during propylthiouracil therapy.