You should seek the advice of a personal injury attorney. Check the Yellow Pages or get a solid recommendation from a friend who can suggest a good attorney. You will also have to document your injuries with a medical report from a doctor. You also need proof that you fell in a McDonald's and that McDonald's was negligent.
If you're uninjured, the answer is obvious. If injury results, call 9-1-1 or go to the closest emergency room. Regardless of where you fall, it is imperative that you get immediate medical attention for any injuries you may have sustained.
You should go to the emergency room to make sure that you haven't injured yourself. Depending on why you fell, McDonald's should be responsible for your injuries.
I would first get up and be sure you didn't get any ketchup or other things on your clothes. I would then continue doing what you were before, and try to be more careful next time.
You should contact the manager of the McDonald's immediately to report the accident. This way, if any serious injury occurred, you can pursue legal action if they were at fault.
If you fell at McDonald's and you can prove that it was as the result of negligence on the part of the employees at the restaurant, you might be able to file a personal injury lawsuit against the McDonald's. Consult an attorney to find out if you have a case.
Go to the staff and inform them that you have slipped. Show them the exact place, where that happened. They will check the spot and if it is wet, they will put a sign there. If it is not wet, they might clean that area.
You should contact an attorney. You should not talk to anyone else about the accident, as that might be prejudicial to your case. You should also see a doctor right away.