Causes of severe vomiting leading to convulsions in one-year-old babies include meningitis, epilepsy, and febrile convulsions (convulsions due to high fever). 1. Meningitis: Meningitis may be caused by infections such as Streptococcus pneumoniae and enterovirus. Patients will have symptoms such as projectile vomiting, severe headache, fever, as well as epilepsy and limb movement disorder. If a one-year-old baby develops meningitis, he or she may have severe vomiting and convulsions. 2. Epilepsy: Epilepsy may be caused by heredity, head trauma, brain tumor, cerebrovascular disease and so on. The patient will have generalized convulsions, increased secretion from the mouth and other manifestations. Therefore, one year old babies with epilepsy will show severe vomiting, convulsions and so on. 3. febrile convulsions: febrile convulsions may be caused by heredity, fever, immature brain development, etc. The patient will show sudden loss of consciousness, rigid shaking of limbs, foaming at the mouth, focal convulsions, etc. If a one year old baby has fever and febrile convulsions, he or she will have severe vomiting and convulsions and other symptoms. One year old baby severe vomiting to convulsions may also have other causes, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.