Diarrhea is a symptom of AIDS, especially chronic diarrhea, but not all chronic diarrhea is AIDS, because there are many causes of chronic diarrhea, such as intestinal tumors and other diseases of the intestinal tract, which may have clinical manifestations of chronic diarrhea. For AIDS patients, in addition to the clinical manifestations of chronic diarrhea, there will be other symptoms, such as prolonged low-grade fever, weight loss, white spots in the mouth, etc. Some patients will have opportunistic infections, and the clinical manifestations will be different depending on the site of infection. For example, pulmonary infection, more commonly known as Pneumocystis carinii pneumonia, patients will have fever, cough, chest tightness, and the symptoms of chest tightness will progressively worsen and may even cause respiratory failure.