Clinical effects of spa therapy were examined in 150 patients with asthma in relation tobronchial hyperresponsiveness and patient age. 1. The efficacy rate of spa therapy was larger as the patient age was higher: the rate was 73.3% in patients under age 49, 81.8% in those between the ages of 50 and 59, 86.4% in those between the ages of 60 and 69, and 90.6% in those over age 70. The mean of efficacy rates was 83.3% in all subjects. 2. The bronchial hyperresponsiveness (BH) was lower as patient age was higher: the BH in patients between the ages of 60 and 69 and in those over age 70 was significantly lower compared to the BH in those under age 49 (p < O.OOl). 3. Clinical effects of spa therapy tended to be lower in patients with increased bronchial hyperresponsiveness. The bronchial hyperresponsiveness showed a tendency to decrease after spa therapy in whom the therapy was effective, however, the BH did not change in patients with slight or no efficacy during spa therapy.