When a 40-day-old baby has a hoarse voice, the specific treatment is as follows: 1. If the hoarse voice is considered to be caused by less water and a drier indoor air environment, the baby’s mental state will be better and will not affect diet and sleep, etc. The baby can be given the right amount of water, while increasing the humidity of the indoor air, the symptoms of the baby’s hoarse voice can be significantly improved. 2. The baby has a sudden hoarse voice and has If the baby is crying and is not in a good state of mind, consider that it is caused by disease factors. There is a disease that babies often suffer from, called acute infectious laryngitis, which is often dangerous, so at this time, according to the baby’s situation, you need to take the baby to the hospital for a detailed examination to clarify the cause of the hoarse voice, and give symptomatic treatment according to the actual cause.