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If you can give your dog Vitamin C supplements, it will recover faster. Like humans, Vitamin C can help greatly in relieving nasal and lung problems like coughs and colds. Vitamin C still is the best anti-infection drug. It can fight most types of infection inside the body, more particularly the ones causing kennel cough.
As much as 500mg of Vitamin C supplement per 10 pounds of your dog's body weight is required. However, Vitamin C is known to cause irritable bowel syndrome, so be careful of giving too much Vitamin C to your dog. You can keep on giving Vitamin C until the infection disappears