| abstract |
An antimicrobial agent for animals is disclosed. The agent comprises as an effective component a racemate of a 3S-type compound of a pyrido[1,2,3-de][1,4]benzoxazine derivative represented by the formula (I): <IMAGE> (I) wherein R is a C1-6 alkyl group, provided that R cannot be a methyl group when the pyrido[1,2,3-de][1,4]benzoxazine derivative is a racemate, or a salt or a hydrate thereof. The compounds possess a low toxicity, are safe antimicrobial agents for animals, have a broader antimicrobial spectrum, and are effective against various infectious diseases of animals. |