The brain is a high-level system that combines “beauty and wisdom” in the human body. Don’t look at the brain melon hard, firm as a city wall, but, if there is a traumatic brain injury, brain tumors and other diseases, or even unknown to squeeze the face of the pimples, the brain inside the contact with the outside world will greatly increase the opportunity. As a result, many small organisms on the outside can take the opportunity to sneak into the human body and make a mess, which can make it difficult to get an intracranial infection. These small organisms can be referred to as pathogenic microorganisms and generally include bacteria, fungi as well as viruses. Intracranial infections in this context generally refer to pathogenic microorganisms like bacteria and fungi; if a virus causes an intracranial infection, it is called viral encephalitis. For the time being, viral encephalitis is excluded from this discussion. Common bacteria that cause intracranial infections include Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and others. It is mainly a bloodstream infection caused by open craniocerebral injury, after craniotomy, and when bacteria from various other sites of infection reach the cranium with the blood. The early stages of intracranial infections occur, usually 2 to 3 days after craniotomy or open craniocerebral injury, with symptoms of fever, headache, and neck stiffness. Once the body fails to stop the onslaught of bacterial and fungal little devils, the symptoms of infection worsen, and it can progress further to high fever, convulsions, seizures, and even coma. Then, of course, there’s the issue of intracranial pressure. The head is filled with cerebrospinal fluid, and the cerebrospinal fluid then puts a certain amount of pressure on the brain, and the normal pressure is 10 to 15 mmHg. If an intracranial infection develops, the intracranial pressure may increase, and the patient will experience dizziness and headaches. If the intracranial pressure continues to increase, brain herniation may even occur until death. Moreover, intracranial infection is a complication after craniocerebral trauma and hyperbaric cerebral hemorrhage, which not only prolongs the hospitalization time and increases the medical cost of the injured person, but also can affect the prognosis of the patient, and in serious cases, it can lead to the death of the patient. Therefore, patients with abnormal postoperative body temperature (persistently higher than 38°C) must be alert to intracranial infection.