Yellow water from the ears of a four-month-old baby is considered to be caused by an eczema infection in the external ear canal. It may be caused by infection or the child’s low immune system, or it may be caused by accidentally flowing into the ear while feeding the child. Early active treatment does not have a great impact, mainly topical medication such as Eudragit or hydrocortisone, and keeping the area clean and hygienic. If the infection is serious and accompanied by pain or acute congestion, a combination of antibiotic ointment, such as Bactrim, is also needed. It is also important to keep the ear dry, clean and hygienic when breastfeeding.