Nosebleeds in two-year-old babies may be caused by nasal foreign bodies, or may be caused by acute rhinitis, thrombocytopenic purpura and other diseases. 1. Nasal foreign body: due to the two-year-old baby is more playful, easy to put the toy into the nasal cavity, if not taken out for a long time, it is easy to lead to nasal mucosal erosion and bleeding, and then there will be a nosebleed. 2. Acute rhinitis: this disease is mainly caused by respiratory viruses, such as coronavirus, adenovirus, rhinovirus, influenza virus, etc., can also be secondary to Streptococcus pneumoniae, Haemophilus influenzae and other bacterial infections. It can be induced by malnutrition, vitamin deficiency and other factors, resulting in children with rhinorrhea, nasal congestion, sneezing, decreased sense of smell, nasal dryness and other symptoms. 3. Thrombocytopenic purpura: the etiology of this disease is more complex, and studies have shown that it is mainly related to genetics, pathogenic microbial infections, autoimmunity decline and other factors. The main symptom is the presence of petechiae on the skin and mucous membranes, often accompanied by nasal bleeding, gum bleeding and other symptoms. The causes of nosebleeds in two-year-old babies are many, and it is necessary to go to the hospital in a timely manner to improve the examination and clarify the specific causes.