With food poisoning, ideally we want the body to eject the noxious product completely out of the systems so we do not supress too soon howver, if your stomach is completely empty but you still feel nauseus then I recommend an antiemetic such as prochlorperazine or domperidone. You may need to get a script for them but ask your pharmacist first. It is important to keep sipping water but dont start to eat until your stomach is settled. Ginger biscuits can be helpful or dry toast.

Food poisoning may then turn into diarrhoa so this information may be useful:

Once the bowel is upset, it then has problems digesting milk.
Avoid milk products for 24 hours
Drink plenty of water
Eat small bland meals
Eat fresh boiled rice as this slows down gastric transit

For adults use loperamide capsules 2mg, up to eight in 24 hours to stop diarrhoea. Cramping can be helped by dimethicone or peppermint oil capsules. Peppermint tea is really good to help settle the digestive tract.

Ensure you keep fluid levels up. If you do all the above, it should settle down in 24 - 48 hours however if you have been abroad recently, or there is blood, mucus or pus in the stool, then see a doctor. Any severe pain or temperature should also be reason to contact the doctor

I hope this information is useful.

Regards