Moxibustion can improve human immunity. Like your little sister, she is usually thin, weak in resistance and often catches a cold, which is mainly caused by physical weakness. Because healthy qi is weak and evil spirits are easy to invade, she will often get sick. You can let your little sister do moxibustion often. The main acupoints of moxibustion, Guanyuan, Qihai and Zusanli, are all health-care acupoints.