Harris Vinegar Weed & Grass Killer is a quick-acting, non-selective contact herbicide containing acetic acid. Foliar contact results in rapid desiccation and control of annual weeds and grasses, and top growth reduction of herbaceous perennial weeds and grasses. Results are often seen immediately after using the weed killer, with browning and shriveling of unwanted weeds. This weed killer is free from chemicals traditionally used in other weed killers. Its concentrated vinegar formula is 4x stronger than average table vinegar and perfect for tackling stubborn weeds.