If you had food poisoning, how soon would you start getting ok after vomiting and having diarrhea?

What poison? Depends in large part on what you are referring to. People use this term to generally describe illness acquired by eating foods, but there are many causes possible, from ingested toxins to bacterial or viral infections. Generally, these acute illnesses last 24 - 72 hrs and resolve without further problems, but must stay hydrated.