You will be surprised to know that 99% of gas produced in your gut is odorless and only about 1% is responsible for making farts smell terrible. That 1% is comprised of sulfurous gases which are usually unpleasant to the nose. According to experts holding in farts is not harmful to health but causes discomfort in the abdomen. Some tips to make your farts less foul-smelling: Have your vegetables cooked, avoid fizzy drinks, reduce dairy consumption and fatty foods and chew your food well.