While at NIH, discovered that frogs produced powerful antibiotics in their skin, which he called Magainins, based on the remarkable healing properties of these animals after surgery. Along with Han Boman in Sweden, and Robert Lehrer at UCLA, he established the widespread existence of antimicrobial peptides throughout nature. His work has led to the discovery of the magainin peptide family in amphibia, and comparable systems in mammals. With colleagues at Penn Dr. Zasloff discovered the underlying basis of pulmonary infections in Cystic Fibrosis to be a malfunctioning of these newly described antimicrobial peptides in the airway of the individuals with cystic fibrosis. Dr. Zasloff and his team have been responsible for the discovery, clinical and commercial development of several compounds, including Pexiganan, a synthetic antimicrobial peptide developed for the treatment of infections in diabetics, the first entirely new class of antibiotic to be developed as a therapeutic in 30 years. In 1993, Dr. Zasloff and his group discovered squalamine in tissues of the dogfish shark, the first of a novel class of steroids, called aminosterols. Subsequently, his group discovered squalamine to be a potent antiangiogenic compound with activity against solid tumors. Squalamine is currently in Phase II clinical trials being evaluated for treatment of non-small cell lung cancer and refractory ovarian cancer. Recently his group reporoted on the discovery of another aminosterol isolated from the shark, called Produlestan, which was shown to act centrally in mammals to control food intake; this compound entered clinical trials in late 2001.