2,4-Dichlorophenoxyacetic acid

2,4-Dichlorophenoxyacetic acid (usually referred to by its abbreviation, 2,4-D) is a common systemic herbicide used in the control of broadleaf weeds. It is a synthetic auxin (plant hormone) and one of the most widely used herbicides in the world. 2,4-D is a possible carcinogen per WHO, and some ester forms are highly toxic to fish and other aquatic life.