How much viatamin c daily take incase of prevent cancer?

No one knows: Despite the "pop" claims and conflicting studies of diet and cancer, hopes that taking vitamin c in tablet form would prevent cancer or enhance overall health have been disappointed. Despite uncertainties, you'd do much better to eat a sensible, balanced diet with plenty of fruits and vegetables. None of the physicians with whom i work take vitamin c or any other "antioxidant" for their own health.

It is a Safe Vitamin: Vitamin-c is commonly used in a daily dose of 500mg. Even higher doses can be taken safely. But there is no convincing proof that it can prevent devlopment of cancer.