The PG content were determined in 62 cases with peptic ulcer and erosive gastritis before and after the treatment of Chinese herbal drugs. The value of PGE2,PGF1 alpha, 6-keto-PGF1 alpha and TXB2 were 96.25 +/- 28.51, 14.24 +/- 13.26, 10.72 +/- 9.14 and 16.51 +/- 12.24 pg/mg respectively before the treatment and were 121.42 +/- 30.02, 18.59 +/- 18.40, 18.79 +/- 12.61, 8.29 +/- 6.27 pg/mg respectively after the treatment. 6-keto-PGF1 alpha was significantly increased (P < 0.01), TXB2 was decreased (P < 0.01), but there were no significant changes in PGE2 and PGF1 alpha. Experimental study also showed that Chinese Herbal drugs played an important role in protecting indomethacine induced ulcer rats.