Bacterial septicemia is a leading cause of mortality in kittens from 10 days to 4 weeks of age. The seriousness of the infection often calls for a broad-spectrum antibiotic to be started prior to availability of culture and sensitivity test results. Treatment with broad-spectrum antibiotics in the kitten represents a particular challenge because of the increased risk of drug toxicity. No studies have been done to guide clinicians in the treatment of kittens with this drug. Enrofloxacin (Baytril™), approved for use in adult cats, is largely metabolized in the liver and excreted by the kidneys. Its use is not common in kittens because appropriate dosing information is not available. These investigators will study the use of this antibiotic in kittens less than 8 weeks of age and will determine the appropriate dosing level and schedule for use in these kittens. This will provide veterinarians with another drug in their arsenal to safely treat bacterial infections in young kittens.