The Consequences of Betrayal

is episode 45 of the Naruto: Shippūden anime.

Synopsis
To confuse and slow down Yamato's wood clone, Kabuto creates a fake corpse, resembling Sai. Naruto, still recovering from the effects of his Four-Tailed state, is told to stay behind by Yamato. However, Naruto tells Yamato he is fine and the trio continue to follow Sai. During their pursuit, the team is forced to take a break when Sakura's own injuries take their toll on her. As she heals herself, Yamato talks to Naruto in solace, and tells him that it was he, in his Four-Tailed form, who hurt Sakura. Naruto is shocked to know this and condemns his own actions.