The actor told USA Today that he dropped acid as research for The Necessary Death of Charlie Countryman, which sees his character take the drug.
"There's a way to do an acid trip like Harold & Kumar, and there's a way to be on acid," he said.
"What I know of acting, Sean Penn actually strapped up to that [electric] chair in Dead Man Walking. These are the guys that I look up to."
However, LaBeouf - who recently claimed that he would have sex on screen for Lars Von Trier's movie Nymphomaniac - said that "there are rules" when it comes to method acting.
"I have ethics," he said. "I'm not completely out of my mind... But I don't think there's anything wrong with sex. Sex is beautiful if it's done right. And I wouldn't just do it for no reason... Sex is different than love, and there is a separation, and that middle gap is what the movie's about."
Nymphomaniac's producers recently clarified that the movie will use body doubles and special effects in its sex scenes.