Aims: To test the effect of glucosamine hydrochloride (glucosamine- HCl) on the proteoglycan (PG) concentration of the articular disc of non-arthritic temporomandibular joints (TMJs) in rabbits. Methods: Twenty-four of 48 New Zealand white 10- to 12-week-old male rabbits (2.2 kg average) were injected with the irritant chymopapain in the knee joint. Both groups of 24 rabbits were divided into 3 groups of 8 animals. The rabbits were fed a control diet or a diet supplemented with glucosamine-HCl incorporated at a level to provide 20 mg/kg (approximating the recommended dose 500 mg/tid/70 kg man) or 100 mg/kg, for 8 weeks. Sulfated glycosaminoglycans (GAGs) were assayed in protease K digests of the TMJ articular disc by dimethylmethylene blue method to quantify PG concentration. The groups were compared with 2-way analysis of variance. Results: Glucosamine-HCl did not cause a significant change in the PG concentration of the TMJ articular disc (P > .8). There was also no detectable effect of chymopapain injection to the knee joint on the TMJ (P > .07) and no interaction between glucosamine-HCl treatment and chymopapain injection (P > .3). Conclusion: Glucosamine-HCl has no effect on PG concentration of the articular disc of non-arthritic TMJ in rabbits. Keywords: glucosamine-HCl, glycosaminoglycans, proteoglycan, rabbit, temporomandibular joint