Ping-Wei San (PWS), a Chinese medical decoction, was used to improve digestive absorption. This study was aimed to determinewhether treatment with PWS reduce gastric ulceration induced by indomethacin and influencing its anti-inflammatory effect. PWS wasextracted with boiling water and the decoction was freeze-dried into powder (H-PWS). The amounts of glycyrrhizin and hesperidin inH-PWS were analyzed by a HPLC method to be 38 and 19 mg/g, respectively. Co-administration of H-PWS resulted in a dose-dependentinhibition of indomethacin-induced gastric mucosal cell death. H-PWS (200 mg/kg) also alleviated the indomethacin-induced gastriculcer in male Wistar rats in vivo. The inhibition effects of NO and PGE2 production were enhanced by indomethancin co-treatment withH-PWS from LPS-stimulated RAW 264.7 cells. H-PWS (200 mg/kg) also augmented the anti-inflammatory effect of indomethacin in1% carrageen-induced paw edema. Moreover, H-PWS co-treatment with indomethacin produced a lower PGE2 level in serum than onlyindomethacin. Based on the results, co-treatment with H-PWS reduced the occurrence of indomethacin-induced gastric ulcers withoutaffecting the anti-inflammatory effect of indomethacin. Therefore, we suggested that H-PWS can be developed as an anti-ulcer drugand H-PWS could be taken with indomethacin to decrease ulceration.