Synthesized at the Sagami Chemical Research Institute and developed by KAKEN, Pentoxazone is an oxazolidinedione-type rice herbicide. In 1997, it was registered as an agrochemical in Japan. Since then, it has been used as an herbicide for paddy rice in its initial formulation and in several mixed formulations based on this initial formulation. Pentoxazone is effective mainly on annual weeds in rice paddies, such as barnyard grass, Lindernia, and Monocholia, and is also widely effective on other weeds including Eleocharis kuroguwai, a perennial weed that is difficult to eradicate. Pentoxazone shows high, stable, and residual efficacy particularly on Lindernia and Monocholia, both of which are resistant to sulfonylurea herbicides. The safety of Pentoxazone is high for rice paddies, and therefore it can be used in a variety of ways. Its initial formulation can be used on rice paddies before or after the rice is transplanted, and its one-shot herbicide formulation can be used at the same time as rice planting. There are also formulations approved for flooding and direct seeding in rice paddies. Having extremely low water solubility and high soil absorbability, Pentoxazone hardly flows out to groundwater and rivers. Furthermore, it has low toxicity to humans, animals, and other living forms. For these reasons, it is an environmentally safe herbicide.