Wild mustard (Brassica kaber) is an annual herbaceous plant with upright stems and yellow flowers arranged in clusters at the tips of the branches and borne on stalks.
All parts of B. kaber contains sinigrin, which in the presence of the enzyme myrosinase, is converted to glucose, allyl isothiocyanate (mustard oil), and potassium hydrogen sulfate. Mustard oils are poisonous. The toxicity, by ingestion, of allyl isothiocyanate has been determined to be 0.001% of the body weight. Also, mustards occasionally contain toxic concentrations of nitrate that may complicate toxicosis.