BG-104, a compound of Chinese herbs, has been reported to exert superoxide scavenging activity (SSA) in cell free systems. This report addresses in vivo effects of BG-104 in various disorders. The plasma SSA and laboratory parameters were determined in patients Behçet's disease (BD), Sjögren's syndrome (SjS) or hematological malignancy (M), and the effects of BG-104 treatment on these parameters were studied and compared with those of another antioxidant, vitamin E (alpha-tocopherol). The plasma SSA was significantly lower both in patients with BD and M, and in patients with SjS without antioxidant treatment as compared to that in healthy controls, and it showed an inverse correlation with disease activities. The treatment with BG-104 and/or vitamin E significantly enhanced the plasma SSA in all disorders studied. Both the erythrocyte sedimentation rates, the absolute number of neutrophils, as well as C-reactive protein levels were significantly lower in patients treated with BG-104 and/or vitamin E than those without these drugs. These results indicate that the BG-104 has an anti-inflammatory effect through enhancing plasma SSA in patients with BD, SjS or M.