We treated 19 eyes of 16 patients who had filamentary keratitis associated with various diseases of the cornea with 5% sodium chloride eyedrops, administered three to four times daily. Filaments associated with acute or traumatic diseases of the cornea responded in all nine cases, with rapid resolution of symptoms and signs (usually within one week). Filaments associated with keratoconjunctivitis sicca responded more slowly (average response time, four weeks); in one of nine cases (11%), the treatment failed. One case of essential filamentary keratitis responded within four weeks. The overall success rate was 95% (18 of 19 cases), with 17 cases (89%) showing dramatic improvement within four weeks.