The main signs of low immunity are easy fatigue, susceptibility to infections, and decreased gastrointestinal function. Immunity refers to the body’s own defense mechanism, which can maintain the health of the body. The main manifestations of people with low immunity are as follows. 1. Easily fatigued: no interest in doing anything, easily tired and listless. Secondly, they are also prone to headache, insomnia and other symptoms. 2. Easily infected: the ability of self-defense decreases, it is easy to be infected with some pathogenic microorganisms. Respiratory tract infections are the most common. 3. Decrease in gastrointestinal function: after eating and drinking, indigestion, bloating, abdominal pain, diarrhea or constipation are easy to occur. If the above symptoms occur frequently, please go to the hospital for examination and treatment.