Mustard oil is far from a common herbal remedy, but it has shown a remarkable ability to eliminate excess flatulence in those who seem to always be passing gas at the most inappropriate times. Mustard oil is very potent, and filled with active ingredients that can soothe the stomach and reduce inflammation. Mustard oil is a very base substance, so it counteracts the acidity in the stomach, which can cause indigestion and an abnormal build-up of gas. Mustard oil can be mixed with rock salt or consumed by itself; very small amounts, less than a spoon, are necessary to prevent flatulence.