Red eyes of five-month-old babies may be caused by excessive eye rubbing, eye trauma, conjunctivitis and so on. 1. Excessive rubbing of the eyes: if a five-month-old baby enters a foreign body in the eye, such as sand, eyelashes, etc., the baby will keep rubbing the eyes, resulting in red eyes. In addition, the baby has no autonomous consciousness, in the air drier environment, will often involuntarily rub the eyes, may also lead to the symptoms of red eyes. 2. Eye trauma: If the five-month-old baby’s eyes are bumped, it may lead to the rupture of small blood vessels in the eye, causing subconjunctival hemorrhage, resulting in the phenomenon of red eyes, accompanied by pain, bruising and other symptoms. 3. Conjunctivitis: when a five-month-old baby suffers from conjunctivitis, it may be caused by allergies, bacteria, etc. Under the stimulation of inflammation, the eyes will be red, accompanied by eye congestion, increased secretions at the corners of the eyes and other clinical manifestations. When a five-month-old baby has red eyes, parents should immediately take the baby to the hospital, under the guidance of the doctor for proper treatment.