Wasting people can be detected by the following ways: medical history, clinical manifestations, imaging examination, endoscopy, etc. 1. Medical history: People with corresponding medical history of unexplained weight loss should consider the possibility of cancer, for example, patients with history of viral hepatitis should suspect liver cancer; patients with long-term inflammatory bowel disease should suspect colorectal cancer; patients with long-term gastric ulcer should exclude gastric cancer. 2. Clinical manifestations: patients with unexplained wasting accompanied by certain symptoms should be suspected of corresponding cancers; for example, lung cancer should be suspected when combined with long-term chronic dry cough; patients with long-term abdominal distension or irregular abdominal pain should be suspected of abdominal malignant tumors, such as gastric cancer, hepatocellular carcinoma and intestinal carcinoma, etc; and patients with enlarged lymph nodes or hemorrhagic anemia should be considered of malignant tumors of the blood system. 3. Imaging examination: Imaging examination is an important means to diagnose or exclude many cancers. Regular ultrasound, CT examination and, if necessary, enhanced CT or even MRI examination can be performed. 4. Endoscopy: endoscopy is the best way to detect or diagnose malignant tumors of gastrointestinal tract, not only can directly observe the lesions in the digestive tract with naked eyes, but also can take biopsies for pathological examination for further diagnosis, patients suspected of suffering from malignant tumors of gastrointestinal tract are recommended to undergo endoscopy. Unexplained sudden weight loss is one of the danger signals of malignant tumors, especially in middle-aged and elderly people. It is recommended that patients go to the hospital as soon as possible, consult a professional doctor with their condition, and rule out or make a clear diagnosis as soon as possible.