Abstract: OBJECTIVE To compare the antioxidant activity and antibacterial activity in vitro of 75% ethanol extracts from Onosma glomeratum and Onosma hookeri..METHODS Antioxidant activity of O. glomeratum and O. hookeri in vitro was measured as ABTS method, ferric reducing ability of plasma(FRAP) method and pyrograllol autoxidation method, while the antibacterial activities on 15 different strains in vitro were studied by broth dilution method. RESULTS The 75% ethanol extracts of Radix Onosmatis had a certain scavenging effect on ABTS free radical and superoxide anion free radical, the effect was equivalent to or slightly better than BHT; the total reducing power were becoming stronger with the increasing of concentration. Two extracts of Radix Onosmatis had certain antibacterial activity to gram-positive bacteria, but had no antibacterial activity to enterobacteriaceae strains and Pseudomonas aeruginosa. CONCLUSION Both of two sources of Radix Onosmatis have some antioxidant and antibacterial effects in vitro.