Smoker’s disease is a cerebrovascular disease that is mainly caused by chronic progressive narrowing or occlusion of the major bilateral branches of the cerebral arterial ring (siphon segment of the internal carotid artery, anterior cerebral artery, middle cerebral artery, and sometimes the beginning of the posterior cerebral artery), followed by abnormal changes in the vascular network at the base of the skull, resulting in the formation of abnormally fragile and fine smoke-like vessels, hence the name smoker’s disease. Some patients ask if there is a difference between smog and smog syndrome. In typical smoldering disease, the lesions are bilateral, with narrowing or occlusion of the major arteries on both sides of the brain and abnormalities in the vascular network at the base of the skull; however, some patients have unilateral lesions, with only the left or right hemisphere having the corresponding lesions, or with a combination of other diseases, which is generally called smoldering syndrome. So, of course, there is a difference between smog and smog syndrome, but sometimes the term is less strict, and sometimes smog syndrome is referred to generically as smog. However, regardless of whether it is typical smog or smog syndrome, both require prompt medical treatment. Currently, combined vascular bypass surgery has been shown to be very effective in clinical practice, as it combines direct bypass and patching to improve the blood supply to the brain tissue and achieve more desirable results. Of course, for smog syndrome combined with other diseases, in addition to combined vascular bypass surgery for smog lesions, other combined diseases need to be treated symptomatically.