Nasolacrimal duct stenosis, which causes epiphora and eye mucus, is generally treated with probing and irrigation of the nasolacrimal duct. A 57-year-old woman was treated with probing and irrigation of the nasolacrimal duct three times, however, her symptoms of refractory nasolacrimal duct stenosis did not improve. Following 3 days administration of saisoin, her epiphora ameliorated. Based on this experience, we treated 11 adult patients with nasolacrimal duct stenosis using saisoin, and 10 (90.9%) achieved remission within a week. All the adult patients had received treatment by probing and irrigation of the nasolacrimal duct at an ophthalmological clinic, and their symptoms had not improved. Two such cases in infants, moreover, were cured with saisoin in a week. This is the first report on the efficacy of saisoin for the treatment of nasolacrimal duct stenosis in Japan.