"Tonsil Trouble" is the first episode in the twelfth season of the American animated television series South Park, and the 168th episode of the series overall. Written and directed by series co-creator Trey Parker, it first aired on Comedy Central in the United States on March 12, 2008. In the episode, Cartman contracts HIV during a blood-transfusion. When Kyle laughs at Cartman's misfortune, Cartman intentionally infects Kyle with his disease as well.