This study was carried out to examine the in vitro effects of alginate (LVA) which is low viscosity alginic acid, on collagen type II synthesis of chondrocytes and the in vivo effect, orally administered, on cartilage degradation. Rabbit articular chondrocytes were cultured in 35 mm dishes and then LVA was treated. The effects of LVA of various viscosity (86.5 cP(LVA1),45.4 cP(LVA2), 21.2 cP(LVA3) and 9.6 cP(LVA4)) and various concentration (50, 100, 200 ${mu}$g/ml of LVA4) on chondrocytes were determined by western blotting assay for the detection of collagen type II production. In western blotting assay, collagen type II production in chondrocytes were 1.00 in control,0.95 in LVA1, 1.41 in LVA2, 1.57 in LVA3 and 1.58 in LVA4. Collagen type II production of various concentration of LVA4 were 1.00 in control, 1.24 in 50 ${mu}$g/ml of LVA4, 1.52 in 100 ${mu}$g/ml of LVA4 and 1.86 in 200 ${mu}$g/ml of LVA4. Osteoarthritis (OA) was induced in 24 rabbits by unilateral anterior cruciate ligament transection (ACLT) and randomly divided into 6 groups. The experimental group was given oral administration of 0.5 ml/kg of saline(control), 12.5 mg/kg of LVA (A12.5), 25 mg/kg of LVA (A25), 50 mg/kg of LVA (A5O), 75 mg/kg of LVA (A75) and 20 mg/kg of aceclofenac (AC) for 6 weeks after ACLT. All knees were harvested at 6 weeks after surgery and cartilage degradation was evaluated. Cartilage degradation in the control group was significantly more severe than that in the A25, A5O and A75 groups but AC group had no significant changes on the macroscopic grading scale.