Thirty patients with allergic conjunctivitis, caused by Parietaria or grass pollens, participated in a double-blind parallel study comparing levocabastine to cromolyn sodium, both given as eye drops. Symptom and sign scores were recorded during a 4-week period. The patients received only these drugs during the time of observation. The evaluation of the clinical signs and symptoms by the clinicians and by the patients revealed a significant improvement of conjunctivitis in all patients. The intergroup comparison was equal in the two groups treated respectively with levocabastine and cromolyn. Therefore, levocabastine and cromolyn are effective in the treatment of pollen-induced allergic conjunctivitis.