Mustard flowers are hermaphroditic and can self-pollinate, so they do not need another plant as a pollen donor. Pollination occurs either by wind or by insects visiting the flowers.

Each fruit (silique) contains roughly a half dozen seeds. The plants are harvested for their seeds just prior to the seed pods becoming ripe and bursting open (dehiscing)

Grinding and mixing the seeds with water, vinegar, or other liquids creates the yellow condiment known as prepared mustard. The seeds can also be pressed to make mustard oil, and the edible leaves can be eaten as mustard greens. Mustard is believed to originate from India, where cultivation remains were found during excavations that date back to around 1800 BC.