HiCustomer

Dogs frequently eat things they shouldn’t. Fatty, greasy foods can cause pancreatitis so straight grease could cause an attack as well. It will definitely cause diarrhea and probably vomiting on its own which you are seeing. Symptoms of pancreatitis vary but include vomiting, diarrhea, anorexia (loss of appetite), weakness or collapse, dehydration, shock, fever, depression, and upper abdominal pain. A dog may indicate abdominal pain by acting restless, panting, crying or wincing when picked up, shaking, standing with an arched back, or lying with the front end down and the rear end elevated

You can read about it in detail here:
http://www.vetcentric.com/reference/encycEntry.cfm?ENTRY=23&COLLECTION=EncycIllness&MODE=full

I would try witholding food until tomorrow morning and if he continues to vomit after eating or develops additional symptoms, I would have him seen tomorrow by your vet.

I hope you find this information helpful.