Vitamin C, or ascorbic acid, is an important nutrient in many foods, such as oranges, red and green peppers, and kiwi fruit. It is also available in supplementary form.

Vitamin C has many important functions in the body, including:
Make collagen, an important protein
To heal the wound
Repair and maintain cartilage, bone and teeth
It works as an antioxidant, which means it can neutralise free radicals -- unstable molecules that can damage cells at the genetic level

Historically, vitamin C was used to prevent or treat scurvy, a disease caused by vitamin C deficiency. Today, vitamin C is considered an "immune booster" and is commonly used as a cold remedy. There is some evidence that taking it may reduce the duration and severity of colds. 1

This article discusses the uses, possible side effects and dosages of vitamin C.

What does vitamin C have to use?
Vitamin C has been used to treat and prevent many diseases, including:
Asthma, a chronic lung disease
Bronchitis, inflammation of the air passages in the lungs
cancer
A cataract, a clouding of the lens of the eye
Chronic or chronic pain
The common cold
COVID-192
Gastritis, an inflammation of the stomach
Glaucoma, an eye condition
Heart disease
hypertension
Osteoarthritis, a degenerative disease of the joints
Parkinson's disease, a disorder of the nervous system

There is not much evidence to support most of these uses. However, there are some promising studies.

Vitamin C deficiency
An estimated 8.4% of the U.S. population does not get enough vitamin C. In severe cases, this can lead to scurvy, although it is rare in the United States.

Symptoms of scurvy include:
Blood stasis
Bleeding gums
weaknesses
fatigue
The rash

Vitamin C deficiency is treated with vitamin C supplements. Some symptoms improved within the first 24 hours of treatment. Others can take weeks to disappear.

In severe cases, bones may be affected. When this happens, surgery may be required.