My 2 year old vomited last night 5 times with no fever, no vomiting since but she now has a fever between 100 & 101f. Is this food poisoning or flu?

Fever and vomiting. Some food poisoning does have fever associated with it. The time of onset of symptoms and history of other people who had the same food getting simialr symptoms can help. Also, viral gastroenteritis usually does not have blood in the stools. There is usually otyher children/adults who have been sick with viral gastorenteritis as well.
Infection. Food poisoning doesn't cause a fever. This is an infection and would benefit from a physician evaluation if not improving.

Related Questions

3yr old vomiting 4 times since 4 am now is 11;00 at first food then seems like mucous no fever yet is it virus or food poisoning what should we do?

Repeated vomiting. More than likely your child has a virus. Take the infant off of all food. Give small sips of pedialyte for two hours. If things stay down. Increase to 1/2glas at time. After six hours start on a bland diet, nothing greasy or fried. Stay off of milk and juice. Restore to normal diet after 3-4 days.
Stomach flu. He might got a stomach flu. It easy to get dehydrated at this stage of disease. Be sure that he takes a plenty of fluids (like gatorade), but give it by small amount (with a teaspoon) every 10 min. If refuse to drink, he would probably need to get to er for a IV fluids hydration.