Vitamin C is important in healing of wounds and bone fractures, and in the overall health of skin, teeth, cartilage and bones. It may also be important in general resistance to infection and disease.

Vitamin C is also an anti-oxidant. Mild deficiencies can cause lowered resistance to infections, bruising, and joint tenderness. Strong deficiencies can cause bleeding, anemia and scurvy. Vitamin C is found in most fresh fruits and vegetables, especially citrus fruits and juices. It is easily destroyed by heat, including the cooking process.

Because the body does not store vitamin C, it is relatively safe to take doses above the recommended daily allowance (RDA) of 60 mg in adults. In the early 1970s, it was suggested that megadoses of vitamin C (e.g. 2-5 times the RDA) could increase resistance to infection, lower cholesterol levels, and treat and prevent cancer. However, later studies found that high-dose vitamin C is no more effective than a placebo in the treatment of cancer or in the severity of colds. Megadoses of vitamin C can cause severe adverse effects: diarrhea and vomiting, iron toxicity, kidney stones. It also interferes with the effectiveness of drugs (such as warfarin and other anticoagulants).