All 813 patients with idiopathic scoliosis who completed their first Schroth physiotherapeutic rehabilitation program at the Katharina Schroth Hospital between 1984 and 1987 were reviewed. The patients were divided into four age groups. In Group I (10–13 years, N = 278), vital capacity in patients treated for the first time improved by 18.94% (445 ml). In Group II (14–17 years, N = 264), the average increase in vital capacity after initial treatment was 16.33% (497 ml). In Groups III (18–24 years, N = 123) and IV (> 24 years, N = 148), the corresponding increases were 15.11% (501) and 13.77% (394 ml), respectively. In the 256 patients receiving repeat treatment, the increases in vital capacity in the respective age groups amounted to just more than half those in the patients treated for the first time. The average increase in chest expansion was more than 20% in all groups at all measuring points. These findings show that a course of inpatient treatment by the Schroth method can lead to an increase in vital capacity and chest expansion so that, even in adult scoliosis patients, effective treatment of the associated restrictive ventilatory disorder is possible.