Early stage of duodenal cancer usually does not show obvious symptoms, but after a certain period of time, it may appear abdominal pain, nausea, vomiting, anemia, and may be accompanied by symptoms such as loss of appetite, fatigue, weight loss, and so on. Duodenal cancer starts insidiously and often has no symptoms or mild symptoms in early stage. With the development of the disease, patients may have paroxysmal abdominal pain, mostly after meals, nausea and vomiting, and may vomit out stomach contents or hangover food. If the tumor compresses the bile ducts, jaundice may develop, manifesting as yellowing of the skin or sclera. Some tumors break down and bleed, may form black stools, or show anemia. In the late stage of duodenal cancer, absorption of nutrients may be affected, and malignant manifestations may appear, such as loss of appetite, generalized fatigue and weight loss. If patients have nausea and vomiting, diarrhea, jaundice and other clinical manifestations, they should raise alertness, consult the doctor in time, find out the cause and treat it positively, so as not to delay the condition.