Articles from LEAVEN: Yeast Infections and the Breastfeeding Family: "Nystatin oral suspension is often the first medication a physician will try for treating an infant with thrush or oral yeast. Nystatin oral suspension must come in contact with the yeast organism to kill it. When treating a baby's mouth, first pour the medication into a small cup, dip a cotton swab in it and paint the baby's mouth - the whole mouth, every nook and cranny. Each time more medication is needed, use a clean swab. Do not dip the swab into the medication bottle itself. "