Multidrug-resistant bacterial, fungal, viral, and parasitic infections are major health threats. TheInfectious Diseases Society of America has expressed concern on the decrease of pharmaceutical companies working on antibiotic research and development. However, small companies, along with academicresearch institutes, are stepping forward to develop novel therapeutic methods to overcome the presenthealthcare situation. Among the leading alternatives to current drugs are antimicrobial peptides(AMPs) , which are abundantly distributed in nature. AMPs exhibit broad-spectrum activity against awide variety of bacteria, fungi, viruses~ and parasites, and even cancerous cells. They also show potential immunomodulatory properties, and are highly responsive to infectious agents and innate immuno-stimulatory molecules. In recent years, many AMPs have undergone or are undergoing clinical development, and a few are commercially available for topical and other applications.