Mustard seeds are the small round seeds of various mustard plants. The seeds are usually about 1 to 2 millimetres in diameter and may be coloured from yellowish white to black Health Benefits Helps in asthma Symptoms of rheumatoid arthritis Excellent for digestion Helps in lowering blood pressure Homemade offers premium quality mustard seeds (Rai). This aromatic spice used in many Indian dishes to enhance the strong flavour in food.