Thanks for posting your question on HCM Tablet Tendomac consists of three components (Chondroitin sulfate +Collagen+Sodium hyaluronate +Vitamin C) It is most commonly prescribed to the patients with osteoarthritis, it is also used for other conditions. It is relatively safe drug well tolerated however, it is known to cause the following side effects: Difficulty breathing, tightness in the chest, swelling of the mouth, face, lips, or tongue in small group of patients. Since most of the components are obtained from the animal source, sometimes this tablet may cause allergic reactions however very rare. I hope your query has been answered up to your satisfaction. Take care.