In all 11 patients with progressive systemic sclerosis (PSS; Barnett type I, 2; type II, 5; type III, 4 cases; male 1; female 10 cases; 45.2 +/- 10.2 years-old), 6 cases of scleroderma spectrum disorders (SSD, male 1; female 5 cases; 51.2 +/- 13.2 years-old) and 7 healthy controls (HC, male 1; female 6 cases; 43.1 +/- 8.4 years-old) were entered to be examined. The plasma endothelin-1 (ET-1) levels of PSS, SSD and HC were 1.98 +/- 0.69, 1.76 +/- 0.39 and 1.15 +/- 0.38 pg/ml, respectively. After the stimulation with the low frequency electrical current, electrical acupuncture, for unilateral side of hand/arm (30 min), the plasma ET-1 levels decreased in 10 cases of PSS treated (1.61 +/- 0.45 pg/ml), but no change of plasma serotonin levels. In 4 of 6 cases of SSD, plasma ET-1 levels increased (2.06 +/- 0.39 pg/ml), however, nitrate levels increased and serotonin decreased in 3 of 5 cases of SSD. In 6 cases of HC treated with the electrical acupuncture, the plasma ET-1 levels increased (1.72 +/- 0.58 pg/ml). Thermographically, 9 of 11 cases of PSS and 5 of 6 cases of SSD showed temporally temperature-elevation of hand/fingers not only in treated sides, but also in non treated sides, although none of 7 HC showed temperature-elevation of hands/fingers. The decrease in plasma ET-1 levels due to the electrical acupuncture was thought to induce the vasodilatation and elevate the surface temperature in patients with PSS. These results will provide an excellent basis to study the efficacy of electrical acupunctural stimulation.