OBJECTIVE To investigate the effects of xianlinggubao (XLGB) on subchondral bone and articular cartilage in the rat osteoarthritis model induced by anterior cruciate ligament transection (ACLT). METHODS Twenty-four 3-month-old female SD rats were divided randomly into 3 groups (n=8): Sham group (group A), ACLT group (group B) and XLGB group (group C). The osteoarthritis model was made by ACLT in groups B and C, the joint cave was sutured after exposure of ACL in group A. After 4 days, XLGB was given at 250 mg/(kgd) in group C and the equivalent amount of saline was given in groups A and B. After 12 weeks, the gross appearance of femoral condyles was observed, the degree of cartilage degeneration was scored by Mankin scoring system. The immunostaining for MMP-13 was performed to investigate the effect of XLGB on prevention of cartilage matrix loss. The bone mineral density (BMD) measurement and bone histomorphometric analysis were done in subchondral bone of right distal femur and proximal tibia after 12 weeks. RESULTS The gross appearance of femoral condyles showed that ulcer in the group C was smaller than that in group B after 12 weeks. The Mankin's scale and IA value for MMP-13 in group C were markedly lower than those in group B (P < 0.05). BMD of the subchondral bone in the group B was significantly lower than those in the groups A and C (P < 0.05). The bone mass in group C were significantly higher than that in group B (P < 0.05). CONCLUSIONS Oral administration of XLGB (250 mg/kg per day) for 12 weeks could prevent the cartilage degeneration of rats after ACLT, down-regulating MMP-13 and increasing subchondral bone mass might participate in this process.