Zachary Taylor (Q11896) 
American general and politician, 12th president of the United States (in office from 1849 to 1850) 
No aliases defined.
Shortly after breaking ground for the Washington Monument on July 4, 1850, President Zachary Taylor, a hero of the Mexican War, fell ill. When he died suddenly a few days later, the cause was listed as gastroenteritis--inflammation of the stomach and intestines.
Some historians suspected that Taylor's death may have had other causes, and in 1991 one convinced Taylor's descendants that the president might have suffered arsenic poisoning... After reviewing the test results, the examiner announced that the arsenic levels in the samples were several hundred times less than they would have been if the president had been poisoned with arsenic.