Biofilms are a major health concern worldwide, and no drugs are licensed to target them. Now, de la Fuente-Núñez et al. describe the identification of a new peptide that prevents the formation, and promotes the disruption, of biofilms that are formed by several pathogens, including Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus and multiple Enterobacteriaceae. Peptide 1018 functions by directly interacting with guanosine tetra- or pentaphosphate, (p)ppGpp — a second messenger that is known to regulate the stringent response — and marking it for degradation. These data establish (p)ppGpp as a new drug target in the fight against biofilms.