2,4-D

herbicide

Also known as: 2,4-dichlorophenoxyethanoic acid, chloroxone

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 13, 2026

Quick Summary

2,4-D is a white crystalline compound used as a weed killer. It is a type of herbicide, which is an agent used to control unwanted plants. 2,4-D was introduced around 1945 and is synthesized from phenol and chloroacetic acid.123

Herbicides offer an advantage over mechanical weed control due to their ease of application and cost-effectiveness. While most herbicides are considered non-toxic to animals and humans, they can harm non-target plants and the insects that depend on them. Some early herbicides, like 2,4,5-T (a related compound to 2,4-D), were later deemed unsafe and discontinued in many countries. Dioxins, which are environmental pollutants, can be generated as by-products during the manufacture of herbicides like 2,4,5-T.24

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

4 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

weed
Chemical control
Introduced then were 2,4-D (2,4-dichlorophenoxyacetic acid), 2,4,5-T (2,4,5-trichlorophenoxyacetic acid), and IPC (isopropyl-N-phenylcarbamate), the first two selective as foliar sprays against broad-leaved weeds, the third selective against grass species when applied through the soil. The new herbicides were revolutionary in that their high toxicity allowed for effective weed control…
Read More
Introduced then were 2,4-D (2,4-dichlorophenoxyacetic acid), 2,4,5-T (2,4,5-trichlorophenoxyacetic acid), and IPC (isopropyl-N-phenylcarbamate), the first two selective as foliar sprays against broad-leaved weeds, the third selective against grass species when applied through the soil. The new herbicides were revolutionary in that their high toxicity allowed for effective weed control…
Read More