Why do cockroaches and rats survive in sewers and other extremely challenging conditions? The answer is that through evolution they have been equipped with antimicrobial peptides (AMPs) that protect them from microbiological insult. In the case of cockroaches and rats, the AMPs are very potent, allowing for these challenging environments [1–3]. AMPs are the most ancient and primitive arm of the human immune system and are expressed in mammals, insects, fungus, trees—virtually every multicellular organism that coexist with bacteria, including bacteria. AMPs cover the outer barriers of our body, such as epithelium and skin, enabling us to live in coexistence with what some consider a complex organ—the microbiome [4]. As we now, through the technological advancements in microbiology, start to comprehend the complexity of the microbiome, we can also appreciate the complexity of the AMP-profile.