For many patients, bariatric surgery results in enduring weight loss and comorbidity resolution, but it is not without risk of complications. Complications necessitating possible surgical intervention include small bowel obstruction, internal hernia, intussusception, anastomotic ulcer, and anastomotic leak. Medical complications include dumping syndrome; osteoporosis; substance abuse; nephrolithiasis; high suicide rates; and nutritional deficiencies, some of which can result in neurologic disorders. Patients need to take daily multivitamins with minerals (containing iron, copper thiamine, and folic acid), vitamin D, and calcium to prevent nutritional deficiencies. Patients also need to consume 1 to 1.5 g of protein per kilogram of ideal body weight daily. Vitamin levels should be assessed on a regular basis to monitor for deficiencies and prevent neurologic sequelae.