The article, which is a review-lecture, reflects the historical milestones in the description and study of cerebral edema (CE) from ancient times to the present. Great attention is paid to the Monroe–Kellie doctrine, without which it is impossible to understand the mechanism of development of a vitally significant complication of CE – intracranial hypertension. The importance of the Monroe–Kellie doctrine in substantiating the symptomatic treatment of increased intracranial pressure is emphasized. The possible involvement of the glymphatic system in both the decrease and the increase in increased intracranial pressure is discussed. The modern ideas about the blood-brain barrier (BBB), its role in the development of CE and an increase in intracranial volume are analyzed. With the study of the molecular mechanisms of BBB damage and the development of targeted therapy, the researchers associate future advances in the treatment of CE. The great interest of modern authors in the state of the BBB in various diseases, as well as in the violation of its integrity in COVID-19 is reflected. It is noted that the main and only, today, method for diagnosing CE is neuroimaging. Development has begun on the isolation of potential biochemical markers of CE from blood.