Vitamin C is essential for the body to fight against infection and disease (osteoarthiritis, feline leukemia, dermatitis, epilepsy, peridontal), promotes healing and relieves pain. A powerful antioxidant it neutralizes free radicals and toxins. Vitamin C can be synthesized by cats and dogs, and therefore there is no dietary requirement for it. However, supplementation of vitamin C is beneficial during stress and when ill. Some human studies have shown it to prevent cataracts. Excellent sources of vitamin C include citrus fruits, green herbs and vegetables, berries and peppers.