What's the best cure for my 1 yo's diaper rash?

Desitin (zinc oxide diaper cream) Original: Desitin (zinc oxide diaper cream) original works well. Make sure you change the diapers frequently, and also prevent the baby from sitting in wet diapers for long periods of time. If this doesn't completely resolve the rash then see your childs pediatrician.

Diaper rash: For diaper rash keep baby's skin clean & dry. Change diaper as soon as it's soiled or wet. For healing allow baby to go without diaper for periods of time so affected area can air out. Avoid tight diapers or airtight covers over diaper. Meds your Dr. might recommend include antifungal cream (for fungus), a steroid cream (for significant inflammation) or an antibiotic (for bacterial infection.)