Chronic pain due to calcific tendonitis of shoulder is a prevalent condition usually treated with recurrent courses of NSAIDs, physical therapy or surgical interventions. Colchicine has been reported to be effective in the acute attack of shoulder tendonitis, however, has never been examined in controlled study in patients with chronic shoulder pain secondary to calcific tendonitis. Eighty patients with chronic shoulder pain (at least 3 months duration) due to calcific tendonitis will be randomized to receive colchicine 0.5 mg twice daily or placebo (lactose capsules) for 4 months. At the end of this blinded part of the study, patients who received placebo and did not improve, will be eligible to continue study in the open mode for additional 4 months with study drug. Efficacy (VAS for shoulder pain, shoulder range of motion and shoulder pain and disability index) and safety (blood tests) follow-ups will be scheduled bi-monthly for all patients.