Introduction : Myofascial pain syndrome ( MPS ) is a common musculoskeletal pain caused by myofascial trigger points ( MTrPs ). MPS can cause local or referred pain, tightness, tenderness, stiffness ,limitation of movement, and local twitch response (LTR) in the affected muscle. MTrPs, which cause referred pain in characteristic areas for specific muscles, restricted range of motion (ROM), and a visible or palpable LTR to local stimulation, are classic signs of MPS. Over 70% of MTrPs correspond to acupuncture points. MTrP is a hypersensitive spot in a taut band of muscle fibers. In clinical practice , the active MTrPs should be inactivated combination with the elimination of perpetuating factors or their underlying pathology.Pathophysiology : Pathogenesis of MTrPs is not understood well , but several hypotheses exist.1. The energy crisis model proposes that direct injury or repetitive overloading of muscle results in sustained release of intracellular calcium and focal muscle hypercontraction leading to muscle ischemia.2. The irritable motor end plate model is described by abnormally increased motor end plate activity with excessive release of acetylcholine at the neuromuscular junction.3. The peripheral sensitization model proposes that peripheral afferents become activated after injury by the release of peripheral nociceptive mediators.4. The central sensitization model proposes that the repetitive incoming nociceptive induces neuroplastic changes in the dorsal horn combination with abnormal descending nociceptive pathways from higher center. Inactivation of MTrPs : Treatment of active MTrPs consist of ;1. Nonpharmacologic treatment ; 1.1 Postural , mechanical , and ergonomic modifications.1.2 Stress reduction.1.3 Massage , electrotherapy , ultrasound , and superficial heat.1.4 Manual therapy or myofascial release.1.5 Therapeutic exercises.1.6 Acupuncture1.7 Chiropractor 2. Pharmacologic treatment ;2.1 Nonsteroidal anti-inflammatory drugs or cox-2 inhibitors.2.2 Tramadol.2.3 Antidepressants.2.4 Anticonvulsants.2.5 Nutritional supplements. 3. MTrP injection therapy ;3.1 Dry needling.3.2 Anesthetic injection.3.3 Dry needling and anesthetic injection.3.4 Steroids with anesthetic injection.3.5 Nonsteroidal anti-inflammatory injection.3.6 Vitamin B12 with anesthetic injection.3.7 Botulinum toxin injection.3.8 Acupuncture points injection. Each injection technique will be discussed during presentation. There is no definitive evidence that one technique is superior to another in long-term outcome. It would be recommended that the technique safest and most comfortable for the patient should be used. But pharmaco-economic aspect should be considered in long-term management. Sukajan Pongprapai M.D.