The action mechanisms of Toki-shakuyakusan (TSS), one of Kampo-herbal medicine, on the clearance of immune complexes and macrophage function were investigated. In the in vivo study, oral administration of TSS enhanced the immune complexes clearance from the circulation in MRL Mp-lpr/lpr mice and C3H/He mice, but no effect was observed in the carbon clearance assay. In the in vitro study, TSS increased the binding of immune complexes to macrophages or Kupffer cells, and the digestion of immune complexes by Kupffer cells. By flow cytometric analysis, the expressions of Fc gamma 11/111 receptors and complement receptor 3 (CR3) on macrophages were increased by the treatment with TSS. Besides, it was also reported that the appearance of the activity was owe to the combination of Angelicae Radix and Atractylodis Lanceae Rhizoma, two of six ingredients of TSS. Both outer and inner dialysate of the extract of Angelicae Radix and Atractylodis Lanceae Rhizoma potentiated the binding of immune complexes to macrophages. Low molecular fraction was further fractionated by using colomn chromatography, and the active components were concentrated in fraction 5-C (named LMW5-C). In conclusion, one of the mechanism of enhancement of immune complexes clearance was thought to due to increase the immune complexes binding to macrophage though augment of Fc gamma 11/111 receptors and CR3 expression. And it was revealed that the active components were not only high moleculer substances but low molecular ones.