Spectrum Chemical stocks a wide selection of quality products including Mustard Oil (Natural). This substance occurs naturally and is found in certain plants of the Brassicaceae family, such as black mustard (Brassica nigra), brown Indian mustard (B. juncea), and white mustard (B. hirta). It takes the form of a liquid and is characterized by pungent taste. It is milder than its synthetic counterpart and is collected by pressing or extracting the oil from the seeds of the plants. Mustard Oil has an unpleasant odor and is an irritant to eyes and skin.