The pharmacological treatment of allergic conjunctivitis includes the use of topical antiinflammatory drugs, i.e. steroids and NSAIDs (nonsteroidal antiinflammatory drugs), such as acetylsalicylic acid (ASA). However, steroids are not suitable in prolonged treatment, as well as in pollinosis in the Mediterranean area, because of their side effects. The present double-blind study evaluates the topical use of acetylsalicylic acid eye drops (1% solution) compared to placebo in the treatment of patients with seasonal allergic conjunctivitis during the period June-July 1990. The patients were randomized and treated with ASA eye drops or placebo eye drops, both applied as one drop in each eye q.i.d. for 14 days. The severity of symptoms was evaluated before and after treatment by the investigator and the patient. An overall judgement of therapeutic response was expressed independently by the patient and the investigator at the end of the treatment. The ASA-treated group improved significantly compared to the placebo-treated group. No serious side effects were observed. The results confirm the clinical efficacy and safety of topical ASA in the treatment of pollen-induced allergic conjunctivitis.