Narrated Sulaiman bin Surad (RA): While I was sitting in the company of the Prophet (SAW), 2 men abused each other and the face of one of them became red with anger, and his jugular veins swelled (i.e became furious). On that the Prophet (SAW) said, "I know a word, the saying of which will cause him to relax, if he does say it. If he says: A'utho billahi minash-Shaitan (I seek refuge from Allah from Shaitan), then all his anger will go away.

Bukhari