The yeast fungus 𝘊𝘢𝘯𝘥𝘪𝘥𝘢 𝘢𝘭𝘣𝘪𝘤𝘢𝘯𝘴 not only uses the toxin candidalysin to cause infections, but also to colonize the oral mucosa inconspicuously – but only in finely balanced amounts. Too little toxin prevents oral colonization, too much triggers the immune system and leads to an inflammatory defense reaction, as an international research team from Zurich, Jena, and Paris discovered. The results were published in the journal Nature Microbiology.