Short bowel syndrome most commonly results after bowel resections for Crohn's disease. The normal human small intestinal length ranges from about 3 to 8 m, thus if the initial small intestinal length is short, a relatively small resection of the intestine may result in the problems of a short bowel. Two types of patient with a short bowel are encountered in clinical practice: those with their jejunum anastomosed to a functioning colon, and those with a jejunostomy. Both types of patient have problems absorbing adequate macronutrients, and both need long-term vitamin B12 therapy. Patients with a jejunostomy also have major problems with large stomal losses of water, sodium, and magnesium. This high-volume jejunostomy output is treated by restricting oral fluids, giving a glucose-saline solution to drink, and using drugs that either reduce gastrointestinal motility (loperamide or codeine phosphate) or secretions (H2 antagonists, proton pump inhibitors, or octreotide). Patients whose jejunal length is less than 100 cm, and whose stomal output is greater than their oral intake, benefit most from antisecretory drugs. In patients with a retained colon, bacterial fermentation of unabsorbed carbohydrate in the colon results in energy being salvaged. However, they have increased oxalate absorption and a 25% chance of developing calcium oxalate renal stones. Thus patients with a colon are advised to eat a high-energy diet rich in carbohydrate but low in oxalate. Patients with a jejunostomy need a high-energy iso-osmolar diet with added salt. Both patient types have a 45% prevalence of gallstones. With current therapy most patients with a short bowel have a normal body mass index and a good quality of life.