Popping a couple of antacid tablets after a spicy meal is fine, but taking too many for too long can lead to potentially serious health problems.

Antacids contain calcium, magnesium or aluminum-each of which in large doses can produce dangerous side effects, says Robert Rude, M.D., USC professor of medicine.

"The side effect depends on which antacids you're taking," Rude says. Antacids that contain calcium, such as Tums, may cause kidney stones if consumed in high quantities for months or years, he says. A single Tums contains 300 mg to 500 mg of calcium. While the suggested dietary calcium intake is 1,200 mg per day, people should consume no more than 2,500 mg of calcium a day, he says.

Another group of antacids, including Mylanta, contains magnesium, which can cause diarrhea when overused, Rude says. The recommended daily magnesium allowance from foods such as spinach, brown rice and milk is 320 mg for women and 420 mg for men. Another 350 mg a day in supplements is acceptable, Rude says.

But people with renal (kidney) disease who take too much magnesium can suffer from low blood pressure, breathing problems or even die. "People who have renal disease should not take magnesium supplements, period," Rude says.

Other antacids contain aluminum which, if taken in large doses for a long time, can lead to osteomalacia-a disease in which the bones become brittle and painful.

People who use antacids because they suffer from chronic heartburn or indigestion could have serious underlying medical problems, Rude warns. These symptoms could stem from peptic ulcer disease or gastroesophageal reflux disease, in which corrosive stomach acid bubbles up into the esophagus.

"A person who continually needs to take antacids should speak with a physician," advises Rude.