I hv recurrent cold,cough and ear allergic infection.hw many vitamin c 500mg pills per day is required for it?

Not needed but good: Well, it was never really required. It is beneficial though. Vitamin C concentrations in the plasma and leukocytes rapidly decline during infections and stress. Supplementation of vitamin C was found to improve components of the human immune system such as antimicrobial and natural killer cell activities, lymphocyte proliferation, chemotaxis, and delayed-type hypersensitivity.