Ischemic foci in the brain cannot disappear once formed. Ischemic foci in the brain refer to small ischemic foci formed when the blood supply to the brain capillaries is insufficient, resulting in local brain tissue ischemia, hypoxia, degeneration and necrosis. Once formed, the necrotic brain tissue and brain cells cannot be regenerated, and permanent foci will remain on imaging. Ischemic foci formation is related to atherosclerosis, and patients should initiate secondary prevention medication for cerebrovascular disease in clinical practice to prevent the re-increase of ischemic foci, prevent the formation of cerebral thrombosis, and prevent patients from forming lacunar cerebral infarction. Patients should also pay attention to low-salt and low-fat diet in their daily diet, avoid high-fat and high-calorie food intake, and eat more fresh vegetables and fruits, especially foods rich in vitamin C, which can regulate cholesterol metabolism and prevent the aggravation of cerebral atherosclerosis.