I-Vitamin C, ekwabizwa ngokuba yi-ascorbic acid, yivithamini enyibilikayo emanzini ebaluleke kakhulu kwimpilo yabantu.Ifumaneka kukutya okuninzi, okufana neziqhamo zesitrasi (ezifana neorenji, iilamuni), amaqunube, imifuno (efana neetumato, iipepile ezibomvu).