Levofloxacin is an antibacterial agent used for the treatment of many types of infections in adults. This is a randomized, double-blind, parallel group, multicenter study to determine the safety and effectiveness of levofloxacin (500 mg once daily for 7 days) compared with ciprofloxacin (500 mg once every 12 hours for 10 days) in adults with uncomplicated infections of the skin and the supportive layers beneath the skin. The study consists of 3 visits: one visit for screening and enrollment, and 2 visits for assessment of safety and effectiveness (one visit on Days 3 - 5 of the study and one visit [post-therapy] 2 - 7 days after the last dose of the study drug). The total duration of patient participation in the study is approximately 2 weeks. The primary assessments of effectiveness include the clinical response to treatment (categorized at post-therapy as cured, improved, or failed) and the microbiological response at post-therapy (the elimination of the disease-causing bacteria, categorized as eradicated, partially eradication, or persisted, determined by patient and by type of bacteria). Safety evaluations (incidence of adverse events, physical examination, and laboratory tests) are performed throughout the study. The study hypothesis is that treatment with levofloxacin is at least as effective and as well tolerated as treatment with ciprofloxacin in patients with uncomplicated infections of the skin and the supportive layers beneath the skin. One levofloxacin 500 mg tablet by mouth, once daily (and a placebo tablet once daily, 12 hours later) for 7 days, followed by one placebo tablet every 12 hours for 3 days; or one ciprofloxacin 500 mg tablet by mouth once every 12 hours for 10 days.