Tigecycline, a glycylcycline related to the tetracycline class of antibiotics, represents a new option for the treatment of complicated intra-abdominal and complicated skin and skin structure infections. It displays favorable activity in vitro against the most common causative Gram-positive, Gram-negative and anaerobic pathogens. In addition, tigecycline demonstrates activity against drug-resistant pathogens such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and organisms (such as Escherichia coli and Klebsiella pneumoniae) producing extended-spectrum beta-lactamases. Tigecycline lacks activity in vitro against Pseudomonas and Proteus spp. In randomized clinical trials, tigecycline administered intravenously twice daily has demonstrated efficacy similar to comparators for a variety of complicated skin and skin structure and complicated intra-abdominal infections. The potential for significant drug interactions with tigecycline appears to be minimal. Dosing adjustment is needed for patients with severe hepatic impairment. The predominant side effect associated with its use to date has been gastrointestinal intolerance (nausea and vomiting).