Poor diet is another possibility, but fortunately it’s something you have some control over in your choice of dog food. For example, choosing a formula with essential fatty acids, vitamins, and minerals may promote healthy skin and a shiny coat, preventing dryness, flakiness, and oiliness, which can contribute to a bad smell. Avoiding dog foods that are difficult to digest or contain excessive fillers also helps, since those foods can result in digestive upset and gas.