Because anidulafungin is generally well tolerated and appears to have limited interaction with other drugs, it is a potential important agent in the treatment of invasive fungal infections. Although anidulafungin is approved for the treatment of invasive candidiasis in adult non-neutropenic patients, dosing guidelines for anidulafungin in (morbidly) obese patients are not available. Subsequently, the pharmacokinetic profile of anidulafungin (as well as other echinocandins) in this specific patient population is still largely unknown. During endoscopic gastric bypass surgery, patients are more prone to various kinds of infection, justifying the prophylactic use of anidulafungin in this specific cohort of patients.