Xanthocillin is an antibiotic derived from Penicillium notatum. In vitro tests have shown that most of the common Gram-positive and Gram-negative pathogens, including Proteus and Pseudomonas pyocyanea, are sensitive to xanthocillin. Xanthocillin participated in the trial in patients with a variety of eczematous and intertriginous eruptions, in all of which bacterial infection was thought to be playing a part. Xanthocillin cream produced results, which were on par with other treatments. Information about the current use of this agent is not available.