The most common cause of flatulence is a change in diet or from the dog eating something spoiled (dietary indiscretion). Most cases of chronic flatulence are caused by a diet that is poorly digested by the dog. These poorly digestible diets cause excessive fermentation in the colon and subsequent gas formation. Soybeans, peas, beans, milk products, high-fat diets, and spicy foods are all commonly associated with flatulence in dogs. Most dogs and cats are lactose intolerant and if they are fed milk or dairy products they will experience flatulence and/or intestinal upset. A dog that is being fed a premium diet and is still experiencing flatulence should be tested for a maldigestion problem with either poor digestion or poor absorption of nutrients from the diet. Dogs that swallow air while eating, especially those that eat rapidly, are more likely to experience flatulence. Overweight, obese, and sedentary dogs are at higher risk for developing chronic flatulence, regardless of diet.