2,3,6-Trichlorobenzoic acid is a post-emergent herbicide. Its formula is .
In the United States, it has been cancelled for use as an active ingredient in herbicide mixtures and is no longer sold in herbicidal products. It was sold in formulations under a wide variety of trade names, including Benzak and Trysben.
2,3,6-Trichlorobenzoic acid causes liver damage. It produces hydrogen chloride gas upon heating, which forms corrosive hydrochloric acid upon contact with skin or other body tissues.