Gout is caused by a chemical in the blood called uric acid (urate). Uric acid is usually harmless, and is made in the body. Most is passed out with the urine, and some from the gut with the faeces (stools). In people with gout the amount of uric acid in the blood builds up. From time to time the level may become too high and tiny grit-like crystals of uric acid may form. The crystals typically collect in a joint. The crystals irritate the tissues in the joint to cause inflammation, swelling, and pain - a gout attack.
