The Hostel director told People that he received the advice from Pitt when they were filming Quentin Tarantino's Inglourious Basterds.
Roth said: "After a scene, Brad had to get next to me for a close-up shot, and he said, 'Damn, you're ripe'. I said, 'I didn’t have time to shower'.
"He said, 'Baby wipes, man, baby wipes. I got six kids. All you've got to do is just take them, a couple quick wipes under the pits. Man, I'm getting p***ed on all day. I don't have time to take a shower'."
Roth added: "I thought that was the greatest tip. My character is called the Bear Jew. If I ever started to smell like a bear, I would just use a couple baby wipes under the armpits, and it made it safe for everyone else to act around me."