Chloral hydrate is mainly used in the treatment of febrile convulsions, persistent epileptic states and other treatments, when the state of the body can not be vaccinated. Chloral hydrate is a central hypnotic anticonvulsant drug. This type of drug is mainly used for the treatment of febrile convulsions (convulsive seizures due to high fever), epileptic status, eclamptic convulsions and other diseases, or sedation before anesthesia. Vaccination is not possible in the above disease states, on the one hand, due to the abnormal state of the body may induce adverse reactions, on the other hand, therapeutic drugs may lead to a decrease in the effectiveness of vaccine protection. In addition, due to the sedative effect of chloral hydrate, it may cover up part of the adverse reaction of vaccine, resulting in untimely disposal, so vaccination is also not recommended during the period of taking medication. Vaccination is generally recommended after recovery or stabilization of the disease. It is recommended to consult the clinician on the specific period of time between vaccinations, depending on the type of vaccine to be administered.