Cationic antimicrobial peptides play a very important role in nature as a first line of defence against attack and damage. However, their application to the clinic has not been very encouraging to date. There are indications that the barriers to their success may now be eroding with companies developing peptides to be more stable, cost effective and targeted to specific indications. These include systemic infectious disease, acne, vaginitis, wound infection and inflammation. In addition, the use of such peptides as modulators of innate immunity in the treatment of infectious disease and inflammation has added a further dimension to the field.