("Proliferative Injection Therapy") involves injecting an irritant solution into the body, generally in the region of tendons or ligaments, for the purpose of strengthening weakened connective tissue and alleviating musculoskeletal pain. Prolotherapy, in combination with chiropractic manipulation and physical therapy, has been reported to alleviate chronic pain.Prolotherapy can be distinguished from sclerotherapy. Sclerotherapy is the use of injections of caustics into the veins, in vascular surgery and dermatology, to remove varicose veins and other vascular irregularities. Prolotherapy is the use of injections in the treatment of connective tissue weakness and musculoskeletal pain. Prolotherapy is also called "proliferation therapy" and "regenerative injection therapy."