Case report—A 56 year old otherwise healthy male tried to quit his habit of smoking up to 16 cigarettes a day on four occasions. Each time approximately 3–6 weeks after he stopped smoking, watery non-bloody diarrhoea developed which also occurred at night. Frequency was 4–6 times per 24 hours. It was associated with a weight loss of at least 4.5 kg. There were no other symptoms. All of his symptoms subsided as soon as he resumed smoking. The diarrhoea also developed when he tried to quit smoking using either nicotine chewing gum or nicotine patches. The rest of …