Lenacil is a uracil-derived chemical herbicide used to control dicotyledons.

[3] The compound can be produced via a condensation reaction between ethyl-2-oxocyclopentanecarboxylate and cyclohexylurea under an environment of phosphoric acid:[4][5] Lenacil is used in the agricultural industry as a selective herbicide to protect sugar and fodder beets.

[6] Lenacil is noted as a potential endocrine disrupting compound.

[7] It is not acutely toxic or genotoxic to mammals, though there is limited evidence the compound is carcinogenic.

Lenacil is noted as particularly damaging to algae and aquatic plants, which is a concern if the compound leaches into groundwater when used as a pesticide.