Authors treated 50 seasonal allergic rhinitis ragweed sensitive patients with a second generation antihistamine, terfenadine containing suspension given twice/day for two weeks in the weeds season of 1996. Nasal (rhinorrhoea, stuffed nose, sneezing, itching) and eye symptoms (hyperaemia, itching, tearing), noted by the physicians and by the patients' diary, blood count, liver function, kidney function and ECG were examined. There was no meaningful difference between the symptoms registrated by the physicians and the patients. It was pointed out that according to both notes at all symptoms there was an improvement already on the 7th day of the treatment, which developed further for the 14th day. The only exception was rhinorrhoea which ameliorated only for the 14th day. ECG deviation related to the terfenadine treatment was not found. Repeated vomiting was experienced at one child. Transitional, slight SGOT, SGPT activity increase appeared in 4 children, the same was observed at two children in se kreatinine and carbamid nitrogen level. Nine patients needed (from the 7th day) supplementary local treatment (cromoglycate eyedrops or nasal spray).