The therapeutic dose of cyclophosphamide is: 2-3mg/kg per day, slightly larger dosage for children than for adults, which can be divided into two oral doses, or the 2-day dose can be added to 20mL of saline for injection and injected intravenously once every other day, or 600-1000mg intravenous shock once a month. The total cumulative dose is 150mg/kg (the total dose for primary nephrotic syndrome is 6-8g, and the total dose for patients with lupus nephritis or small-vessel vasculitis is no more than 36g, but the total amount in our hospital is usually about 12g). Blood leukocytes and liver function should be checked regularly during the dosing period (especially 1 to 2 weeks after dosing). If the blood leukocyte is ≤3×109/L, the dose of this drug should be reduced or suspended. You can take compounded cyclophosphamide orally, the total dose is about the same as intravenous. One tablet of 50 mg can be taken twice a day for young people and one tablet a day or every other day for the elderly, about 5-7 boxes (6-7.2 g).