Candidalysin is a 31-amino-acid peptide toxin that the hyphae of Candida albicans secrete. It was identified in 2016. It pokes holes in epithelial membranes and drives mucosal inflammation, and its role in oral and vaginal candidiasis is well established. What is not established is the idea that candidalysin explains invasive candidiasis in critically ill patients. Human evidence stays thin, and several common ICU Candida species never make the toxin at all. Why this matters Invasive candidiasis kills a meaningful share of the patients it strikes, and most of those patients never get a positive blood culture before treatment starts. When someone proposes a mechanism that could link a single fungal…