Claim: Doc Holliday was diagnosed.

John Henry `` Doc '' Holliday -LRB- August 14 , 1851 -- November 8 , 1887 -RRB- was an American gambler , gunfighter , and dentist , and a good friend of Wyatt Earp . He is most well known for his role as a temporary deputy marshal in the events leading up to and following the Gunfight at the O.K. Corral .   At age 21 Holliday earned a degree in dentistry from the Pennsylvania College of Dental Surgery . He set up practice in Atlanta , Georgia , but he was soon diagnosed with tuberculosis , the same disease that had claimed his mother when he was 15 , having acquired it while tending to her needs while she was still in the contagious phase of the illness . Hoping the climate in the American Southwest would ease his symptoms , he moved to that region and became a gambler , a reputable profession in Arizona in that day . Over the next few years , he reportedly had several confrontations . While in Texas , he saved Wyatt Earp 's life and they became friends . In 1880 , he joined Earp in Las Vegas , New Mexico and then rode with him to Prescott , Arizona , and then Tombstone . In Tombstone , local outlaw cowboys repeatedly threatened him and spread rumors that he had robbed a stage . On October 26 , 1881 , Holliday was deputized by Tombstone city marshal Virgil Earp . The lawmen attempted to disarm five cowboys , which resulted in the Gunfight at the O.K. Corral .   Following the Tombstone shootout , Virgil Earp was maimed by hidden assailants and Morgan Earp was murdered . Unable to obtain justice in the courts , Wyatt Earp took matters into his own hands . As the recently appointed deputy U.S. marshal , Earp formally deputized Holliday , among others . As a federal posse , they pursued the outlaw cowboys they believed were responsible . They found Frank Stilwell lying in wait as Virgil boarded a train for California and killed him . The local sheriff issued a warrant for the arrest of five members of the posse , including Holliday . The federal posse killed three others during late March and early April , 1882 , before they rode to the New Mexico Territory . Wyatt Earp learned of an extradition request for Holliday and arranged for Colorado Governor Frederick Walker Pitkin to deny Holliday 's extradition . Holliday spent the few remaining years of his life in Colorado , and died of tuberculosis in his bed at the Glenwood Springs Hotel at age 36 .   Holliday 's colorful life and character have been depicted in many books and portrayed by well-known actors in numerous movies and television series . Since his death , researchers have concluded that , contrary to popular myth-making , Holliday killed only one or two men .