Aplastic anemia is a bone marrow failure syndrome, which simply means that the bone marrow's function to produce blood cells is impaired, and it cannot produce the blood cells needed by a normal body. Clinically, it manifests as a series of symptoms caused by the reduction of all blood cells. A reduction in white blood cells can lead to infections in various systems, such as fever, cough, sputum, abdominal pain, diarrhea, frequent urination, urgent urination, and pain during urination. A reduction in red blood cells leads to anemia, which can cause symptoms such as dizziness, headache, fatigue, chest tightness, and palpitations. A decrease in platelets can lead to spontaneous bleeding, such as bleeding in the mouth, gums, and nose, and in severe cases, even cerebral hemorrhage.