Myofascial pain syndrome (MPS) is characterized by the presence of trigger points, palpable muscle abnormality (fibrocystic nodule) and referred pain distal to the trigger point. Most of the treatment methods for MPS are aimed to reduce the pain in trigger points and reduce the muscle spasm. Botulinum toxin has been studied in MFS eradication because an activation of toxin might be able to block a release of acetylcholine at the presynaptic terminal resulting in a muscle relaxation. Therefore, the pain is relieved by preventing the release of pain neurotransmitters at the sensory neuron.