Zachary Taylor was 12th President of the United States. The last Whig president, "Old Rough and Ready" spent 40 years in the US Army, racking up significant military victories in the War of 1812, the Black Hawk War, the Second Seminole War, and the Mexican-American War. Outwardly apolitical, he was essentially recruited to be a presidential candidate, much like the modern day efforts to draft military men like Colin Powell or David Petraeus, despite the fact that no one was really sure of what their politics are. Taylor ran as a Whig, but ignored much of the Whig agenda.
A mere sixteen months into his presidency, Taylor attended Independence Day celebrations and a groundbreaking ceremony for the Washington Monument. Fatigued by the oppressive July heat, he consumed a bowl of raw cherries and a pitcher of ice cold milk. He became increasingly ill, perhaps with gastroenteritis, and the medical science of the day was unable to diagnose him properly or treat him with anything beyond generic medicines and bleeding. Only July 9, 1850, he was vomiting green and died that evening. He had served the third shortest term as president.
That is the official story. Dissenters claim that Taylor's unknown illness was actually poisoning. The case is laid out by Michael Parenti in his book History as Mystery. The culprits were likely pro-slavery Southerners. Though a slave holder, Taylor was a moderate on the issue and wanted to allow new states in the southwest to outlaw slavery, which angered the South. His successor, Millard Fillmore, signed the Compromise of 1850, which punted the slavery issue to his successors and included the odious Fugitive Slave Act. There were no witnesses to exactly what Taylor consumed and none of it was ever tested.
A retired University of Florida professor named Clara Rising pushed Taylor's heirs to allow an exhumation, which was conducted in 1991. The Kentucky Chief Medical Examiner concluded that Taylor was not poisoned by arsenic, which was about the only thing they could test for since it is preserved in hair. Officially, the cherries and milk were still the culprit. But Parenti and others take issue with how the tests were performed and assert the levels of antimony found could possibly indicate poisoning as well. There is so far, however, no historical evidence of any plot to kill Taylor.