"Instead he wanted bacon but they didn't have any bacon either.:
During the scuffle in Liverpool, Merseyside, the employee, who has now been suspended, brutally headbutts the man before he defends himself by attempting to punch him, missing his face and instead knocking off the man's glasses.
Another female customer, who appears to be in her early 20's - tried to pull the pair off and shouted "it's a f****** joke" before the video cuts off.
A source said: "The staff member in question was behind the counter and took a disliking to the customer.
"He had to take at least a 20 second walk around the counter to come face to face with the customer and that's when the altercation took place."
"There was no security in sight and the guy was covered in blood.
"Me and my friends were left shaken by the event and when asked McDonald's staff what they were going to do about it they said nothing was going to be done."
A McDonald's spokesperson said: "We take matters like this extremely seriously and can confirm the individual has been suspended; an internal investigation is taking place as a matter of urgency."