Pancreatitis:

Pancreatitis is inflammation in the pancreas which is a 'digestive' organ.
When a dog gets pancreatitis they usually throw up, and may have a tender belly. Their appetite may decline. Diarrhea can sometimes happen.
Pancreatitis is rarely fatal but it does happen sometimes.
One of the KEY TREATMENTS for pancreatitis is ## NO FOOD ##
So you stop feeding
Keep them drinking
Later you offer tasteless, dry "food" and hope they won't eat. If the pancreas has NOT healed, they won't eat plain dry food. ## GOOD!! ##
The next food you offer (at the doctor's instruction) would be the lowest fat version of what you normally feed with NOTHING on it as an enticement. Again, LET MOTHER NATURE DETERMINE WHEN THEY ARE HUNGRY ENOUGH.
Sometimes pain medicine is needed. Often bloodwork is needed to confirm the dignosis.
Antibiotics can also become important depending on how the dog's doing. It's very possible for germs to climb up out of the intestine and find purchase in the diseased pancreatic tissue.

Pancreatitis: Drink but not eat. Control vomiting. Avoid dehydration. Maybe pain medicine. Maybe antibiotics.

NO FAT IN THE DIET afterwards. That's how pancreatitis is prevented later.

Illustrated EXPLAINER About Pancreatitis