Nutritional fluids may be given after arachnoid cyst surgery if there is a nutritional deficiency. On the contrary, a light diet is sufficient. Arachnoid cysts are congenital malformations that often occur in the lateral fissure area and the pontine cerebellar angle. They are benign, non-tumor cystic space-occupying lesions outside the parenchyma of the brain, formed by arachnoid membranes encapsulating colorless, transparent cerebrospinal fluid. Most patients with arachnoid cysts are asymptomatic, while some may experience increased intracranial pressure and seizures. Patients with symptomatic arachnoid cysts can be treated with surgery and postoperative care if necessary. If the patient has obvious nutritional deficiencies after surgery and is unable to eat normally, he or she can choose to receive nutritional fluids to supplement nutrition. On the contrary, it is necessary to eat a normal diet, and keep the diet light. It is recommended that patients with arachnoid cysts should take into account their own situation and cooperate with doctors to give appropriate examination and treatment without delay.