Amnesia syndrome, also known as amnesia-fiction syndrome, is mainly due to brain dysfunction caused by vitamin B1 deficiency and may be associated with chronic alcoholism and severe malnutrition. The main manifestations are memory impairment, cis- and retrograde memory forgetting, abnormalities in temporal orientation, and fictitiousness. Therefore, many elderly people may not remember what happened after the onset of the disease, and if the disease further worsens, they may have problems with temporal orientation, i.e., they do not know what time it is. In addition, there will be paraclinic and retrograde amnesia, i.e., memory loss before and after the onset of the disease, and when memory is missing, they will make up things, such as feeling confused about what happened, thinking that things happened that did not happen, and filling in the missing memories with fictitious situations. Therefore, patients who have been drinking alcohol for a long time, have memory loss and chronic malnutrition should be aware of the need to seek medical attention. Amnesia syndrome is mainly a vitamin B1 deficiency, so it is more related to long-term alcohol consumption and severe malnutrition, resulting in gastrointestinal digestive and absorption dysfunction and reduced intake of B vitamins, which can lead to abnormal brain function. Therefore, for people at risk, including those who lose weight, long-term alcohol consumption and elderly people who eat poorly can suffer from malnutrition, it is important to pay attention to the occurrence of similar situations.