Natural Factors Vitamin C - 1000 mg - Bonus Size - With Bioflavonoids & Rosehips - Extremely effective for inhibiting the body's production of histamine during colds - reducing symptoms of water eyes and runny nose. Large doses also help make the digestive and urinary tracts more acidic, inhibiting bacteria and yeast growth. Natural Factors Vitamin C 1000 mg includes the benefits of Bioflavonoids and Rose Hips for added support. Vitamin C is a well-known, proven and powerful antioxidant, derived from diet or supplementation, essential for boosting immune functions, balancing cholesterol, assisting the absorption of iron, and necessary for the maintenance of healthy bones, teeth, gums, skin and blood vessels.