Did you know… Dogs don’t need Vitamin C?! While humans are increasing their Vitamin C intake to support our immune system during these troubled times, dogs can synthesize their own, and do not need an external source or supplement. So before you decide to share an orange with your pup- DON’T! Not only are sources of natural Vitamin C unnecessary for dog’s basic nutritional needs, they are down-right dangerous. Oranges are high in sugars and can cause GI upset.