The book scorpion (Chelifer cancroides), only a few millimetres long, is the best-known member of the pseudoscorpions, an order of arachnids, in Central Europe. It hunts house dust mites, bark lice and book lice in living spaces. It also kills pests in beehives. It often uses its venom to do so. For the first time, researchers in Hesse, Germany, have comprehensively characterised the components of this venom – and discovered molecules with a strong effect against so-called hospital germs. The results may help to combat difficult-to-treat infectious diseases in the future.