High doses of vitamin C do not cure cancer. Vitamin C belongs to the nutritional medicine, can supplement vitamin C. Used to assist in the treatment of scurvy, but also used in a variety of acute and chronic infectious diseases and purpura and other conditions of adjuvant therapy. Patients with cancer should not blindly use drugs to avoid adverse reactions with vitamin C. Vitamin C adverse reactions: can cause urate, oxalate stones. Overdose can cause diarrhea, rash, frequent urination, headache, nausea, vomiting, stomach cramps and so on. Contraindications: contraindicated in patients allergic to vitamin C. Precautions: It is not suitable for long-term overdose of vitamin C, if a large dose of prolonged use of this product suddenly stop the drug may appear symptoms of scurvy. Large doses of vitamin C in pregnant women can induce neonatal scurvy. Cancer patients should not blindly take a large amount of vitamin C; if the body is not feeling well, we should actively consult the doctor, do not believe in the prescription, so as not to cause damage to the body.