The patent on Prilosec, a stomach acid reflux drug made by London-based AstraZeneca (nyse: AZN - news - people), expires in April 2001, although it will likely be extended six months.

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Oral bisphosphonates -- which include drugs such as Fosamax and Boniva -- can upset the stomach and cause acid reflux, although it helps to take the medication as directed.

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Some 20% of Americans experience symptoms of reflux of stomach contents at least weekly, including a burning sensation in the chest or throat or regurgitation, according to the National Institutes of Health.

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Soda is also associated with symptoms of gastro-esophageal reflux disease, when the contents of the stomach leak back up and cause a burning sensation in the esophagus.

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As for surgery, think twice before undergoing anti-reflux surgery, during which the top of the stomach is wrapped around the esophagus to keep stomach contents from backing up.

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Doctors can sometimes see the cancer coming years earlier when acid reflux causes cells in the esophagus to mutate to become more like stomach tissue, a condition called Barrett's esophagus.

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