Gastrectomy for weight loss, or minimally invasive lower sleeve gastrectomy, is safe. The worldwide statistical mortality rate is only 0.1%-0.5%, which is lower than that of laparoscopic cholecystectomy, and the chance of complications is extremely small. Early complications are mainly bleeding and anastomotic fistula. Bleeding is divided into gastric and abdominal bleeding, which can be handled by conservative treatment, adequate drainage, and band-membrane stent; if anastomotic fistula occurs, it can be surgically repaired or bypass surgery can be performed. Distant complications of undigested changes in the digestive tract cause impaired absorption of nutrients and require supplementation of nutrients or micronutrients.