We have evaluated the efficacy of nedocromil sodium 1% nasal spray in 29 patients (14 males and 15 females, mean age 23 years) who had been suffering from seasonal allergic rhinitis due to Parietaria for at least three years. Diagnosis was based on medical history, skin prick test and RAST. Nedocromil sodium was given for 4 weeks in May, at the dosage of 4 mg, 4 times a day in each nostril. On a daily diary card patients had to record both the severity of symptoms following an arbitrary score from 0 to 3 and the possible presence of side effects. After 4 weeks of treatment patients obtained a statistically significant improvement of the symptoms considered (p < 0.001). No side effects have been reported and no other drugs have been necessary to control the symptoms.