Leukocyte 3.3×10⁹/L is mildly low, whether it is serious or not depends on the etiology. Clinically, the normal value range of white blood cells is (4~10)×10⁹/L, so white blood cells 3.3×10⁹/L is a mild decrease, which can not be considered as serious, but it should also be combined with the patient’s condition, if the patient’s condition is bad, or leukemia, then it can’t be used as a measure of this index alone. Decrease in the total number of white blood cells can be seen in gram-negative bacilli or viral infections, aplastic anemia, hypersplenism, hypoproliferative leukemia and so on. Although the patient’s leukocytes 3.3×10⁹/L is not considered serious, some diseases will change faster, and need to be combined with the patient’s clinical manifestations and further examination to make a clear judgment, which requires the help of a professional doctor. White blood cells 3.3 × 10⁹ / L is a mild decline, whether it is serious depends on the primary disease, such as leukemia is more serious, but if the drug caused by it is not serious, but also need to consult the regular hospital in time.