The general symptoms of low immunity are poor mental status, fatigue, dizziness, fear of cold, poor sleep, etc. The body depends on normal immunity to maintain a healthy state. In children, low immunity can lead to poor brain development, mental retardation, and malnutrition. Adults with low immunity are prone to intestinal discomfort, diarrhea and acute gastroenteritis, because low immunity causes external bacteria, viruses, fungi and other substances to invade the body, so it is easy to get infectious diseases, such as frequent colds, fever, runny nose and so on. When a cold is followed by a long time to recover, it takes a long time to take medicine. Or cold or cough for a long time is not good, slowly delayed will develop into rhinitis or pneumonia, and in serious cases is prone to cancer.