Botanical name: Brassica nigra
Other names: mustard see, siddharthaka, sarsapa, rajika
Family: Brassicaceae
Part used: seed
Taste (rasa): pungent, bitter
Characteristic (guna):
Energy (veerya): heating
Post digestive effect (vipak): pungent
Quality (guna): light, dry, penetrating
Dosha effect: effect KV-, P+
Action (karma): Appetiser, digestive, vermicide, increases the appetite, redirects the flow of vata downwards, carminative, expectorant, analgesic, rheumatic.
Dose: 1-6 grams per day 
Contraindications: Signs of heat, inflammation and high pitta.  No drug-herb interactions known.
These little black or brown seeds have a warming and stimulating effect on the digestion and lungs.  A wonderful home remedy for nipping the onset of a cold in the bud.
 
Digestion: Mustard seed clears accumulations of food caused by low agni (digestion), high kapha and ama (toxins).  It warms the digestive system, stimulate agni and clears sluggish congestion due to excess intestinal mucous.  It is also used to kill worms.
Lungs: It is a great expectorant; clears white, sticky phlegm from the respiratory tract.  Mustard seeds are beneficial in kapha-vata breathing problems – asthma, bronchitis, pneumonia.  Also useful in colds.
Joints: Useful in arthritis caused by a cold, wet, damp environment and lifestyle.  Clears ama (toxins) and regulates vata.  Can prevent pain and swelling.  Commonly used as a massage oil for constitutional kapha conditions.
 
Ref: ‘Ayurvedic Medicine’ by Sebastian Pole; ‘Ayurvedic Pharmacology & Therapeutic Uses of Medicinal Plants’ by Vaidya V.M. Gogte; ‘Yogi of Herbs’ by V. Lad & D. Frawley