In TCM, the body is seen as a delicate balance of two opposing and inseparable forces: yin and yang. Yin represents the cold, slow, or passive principle, while yang represents the hot, excited, or active principle. According to TCM, health is achieved by maintaining the body in a “balanced state”; disease is due to an internal imbalance of yin and yang. This imbalance leads to blockage in the flow of qi (vital energy) along pathways known as meridians. Qi can be unblocked, according to TCM, by using acupuncture at certain points on the body that connect with these meridians.
From a western medical perspective, the insertion of hair-fine sterile and disposable needles into the subcutaneous layers of the skin can have profound influences on several regulatory systems.
When used correctly, acupuncture has neurophysiological affects that can release pain-reducing endorphins; affect the metabolism of serotonin, a neurotransmitter (brain chemical) that affects both pain perception and mood; and improve circulation and immune function. Acupuncture specifically works to relieve nausea by releasing chemicals that control the vomiting centre in the brain as well as decreasing acid secretion and inhibiting abnormal gastric contractions.