Topical corticosteroid eye drops are commonly used for ocular sarcoidosis. That systemic absorption of corticosteroids by eye drops may influence the clinical course of sarcoidosis may be speculated because it has been reported that the serum concentration of corticosteroids after drop administration was dose-related. To evaluate the effects of corticosteroid eye drops on the clinical course of patients with stage I pulmonary sarcoidosis, we compared the serum levels of angiotensin converting enzyme (ACE) and bilateral hilar lymphadenopathy (BHL) on chest radiographs of group CS, which is consisted of patients who received topical therapy of betamethasone in the form of eye drops for anterior uveitis, and group CN, which is consisted of patients who did not receive any medications throughout the entire course of the disease. Although the serum ACE level was not significantly different between groups CS and CN at the time of the diagnosis of pulmonary sarcoidosis, the level of serum ACE in group CS was significantly higher than that in group CN 20 months after the topical corticosteroid treatment (24 IU/ml and 16 IU/ml, respectively). Further, the size of BHL on chest radiography in group CS was significantly larger than that in group CN 20 months after the topical treatment (82% and 37% of before control, respectively). These findings suggest the possibility that the topical corticosteroid therapy influenced the clinical course of pulmonary sarcoidosis, inducing some delay in the spontaneous remission in the longterm course.angiotesin converting enzyme; bilateral hilar lymphadenopathy; betamethasone eye drops; spontaneous remission; pulmonary sarcoidosis