Children’s inability to stand on their legs after fever may be related to dehydration and electrolyte disorders caused by fever, and increased metabolic products of the body. 1. Dehydration and electrolyte disorders: children in fever may cause body dehydration, even electrolyte disorders, if the lack of trace elements and water, may make the whole body is very sore or pain, so the child may not be able to stand up on both legs after fever. 2. Increase in body metabolites: If the child is due to poor resistance, infected with bacteria or viruses caused by upper respiratory tract infections, there may be a fever, which leads to an increase in the body’s metabolism, these metabolites will continue to accumulate and stimulate the body, resulting in muscle pain, fatigue, etc., the phenomenon of the child can not stand up. Children can not stand up after fever legs may also have other causes, such as polio, etc., 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, the above medication as prescribed by the doctor.