Conjunctivitis is suspected in a four year old baby with red blood in the eyes. Conjunctivitis is caused by infectious and non-infectious factors. Infectious factors are infections by pathogenic microorganisms, such as bacteria, viruses, fungi and allergic reactions. Non-infectious factors are caused by localized or systemic symptoms, so it depends on your baby’s condition to determine which factor it is caused by. If it is caused by infectious factors, you need to go to the ophthalmology hospital in time for diagnosis and treatment, and choose the appropriate medication for your baby under the guidance of the doctor, which can effectively alleviate the situation of red blood. If it is caused by systemic diseases, it is also necessary to deal with the original disease, and at the same time to treat the redness of the blood, should not be ignored. Lifestyle habits should also be paid attention to, do not let the baby with unhygienic hands to touch the eyes.