Anemia can cause cardiovascular, neurological, digestive, reproductive and urinary system symptoms, as follows: 1. Cardiovascular system manifestations: Palpitations and shortness of breath after physical activity are the most common symptoms. In case of severe anemia or heart failure, palpitations and shortness of breath may occur even at rest. Patients with coronary artery lesions may develop angina pectoris. Some patients who normally do not have angina pectoris may develop angina pectoris if the degree of myocardial ischemia is aggravated by anemia. On physical examination, a soft mid-systolic murmur can often be heard in the fundus or apical region. The heart is often enlarged in patients with chronic anemia. After the anemia is corrected, both the murmur and the enlarged heart may disappear. In severe anemia, a “high output state” may occur. The clinical features of the “high output state” are: dilated jugular veins with increased pressure, dilated peripheral vessels with trapped veins and capillary pulsations, warm skin and possible flushing. Inadequate myocardial compensation may lead to congestive heart failure. Common ECG changes include decreased S-T segment, flattened or inverted T waves, and mostly normal QRS waves. When the anemia is corrected, the above ECG changes can return to normal. Patients with severe anemia, even without heart failure, often have mild swelling of the lower extremities when they wake up. The reason for this may be related to the temporary increase of venous and capillary pressure during activity, the increase of capillary permeability and sodium retention. 2. Neurological manifestations: When anemia is severe, neurological symptoms are also common, especially in elderly patients. Common symptoms include dizziness, headache, tinnitus, blurred vision, black spots or “gold stars” in front of the eyes, lack of energy, lethargy, drowsiness, difficulty in concentration, slow reaction, numbness, coldness or pins and needles sensation. In severe cases of anemia, fainting may occur. If anemia occurs sharply, the patient is often irritable and restless. 3. Digestive system manifestations: Loss of appetite is one of the most common symptoms. Abdominal distension, discomfort in the heart and stomach, nausea and constipation may also occur. Sometimes there may be tongue pain and smooth tongue coating. In severe anemia, the liver may be mildly enlarged, especially in the case of heart failure, and there is often pressure pain. 4. Reproductive system manifestations: Female patients often have irregular menstruation, and amenorrhea is the most common. Anemia is often caused by excessive menstruation, but occasionally anemia can also cause excessive menstruation. Patients with severe anemia often have decreased libido. 5. Urological manifestations: A small amount of protein may appear in the urine of patients with severe anemia, and the urine concentration function is mildly reduced, but it usually does not cause an increase in blood urea nitrogen, except for the existing kidney disease. When acute intravascular massive hemolysis occurs, the urine color can be black tea or soy sauce-like color (hemoglobinuria), and if there is also circulatory failure, oliguria, anuria and acute renal failure can occur.