Qi: This is also called life energy or vital energy. The belief is that it runs throughout your body. It’s always on the move and constantly changes. Acupuncture treatments often focus on ways to promote and maintain the flow of qi.Yin and Yang: These are opposites that describe the qualities of qi.Yin: night, dark, cold, feminine, negativeYang: day, light, warm, positive, male The belief is that everything in life has a little bit of its opposite, too, and balance is the key. For example, a drug from your doctor might heal disease. But it’s dangerous if you take too much of it.According to acupuncture, these ideas play out in our bodies. When you balance the yin and yang of Qi, you feel healthy and well. If they’re out of whack, you feel sick. Acupuncture aims to create harmony and a healthy flow of qi.