Diaper rash, also known as diaper dermatitis, is an inflammation of the baby's skin in the diaper area caused by moisture, friction, and the chemical reaction between urine and stool. The most effective treatment consists of regular changing, allowing the skin to air out, gentle cleansing without perfume, and consistently applying a barrier ointment with zinc oxide and/or calendula. Cornstarch and olive oil are popular home remedies but are not scientifically recommended. In the case of a fungal infection (Candida), medical treatment is necessary.