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. J OROFAC PAIN 2003;17:251–253.