Sudden memory loss in the elderly may be a manifestation of pre-Alzheimer’s disease, or it may be caused by insufficient blood supply to the brain. Alzheimer’s disease is a degenerative disease of the nervous system that occurs mostly in the elderly. Early on, patients may experience near-memory loss, which can be manifested by not being able to remember what they just said or did, often forgetting phone numbers and forgetting to turn off the gas, and some patients may also experience transient memory loss. In case of insufficient blood supply to the brain, it may cause ischemia and hypoxia in the brain. In severe cases, patients may suffer from memory loss and inattention, which may also cause patients to lose their memory. The main treatment is to improve blood circulation. Commonly used medications are Shuxin and Vibrulun, and salvia and safflower can also be applied. If it is considered a manifestation of pre-dementia, oral olanzapine, piracetam and cytarabine may slow down the patient’s condition.