Firstly you need to identify whether you are actually suffering from food poisioning or whether its a stomach bug. With food poisioning onset usually happens anywhere from 30 mins to 72 hours and you will be greeted with projectile vomiting, cramps and fever. Make sure that you sip water frequently and dissolve an aspirin in water and sip that. This helps with the pain and the sickness. Once the sickness has stopped the diarrohea starts and that can last up to 5 days. Again you need to keep drinking fluids and once you start eating again remember the BRAT diet- Bananas, Rice, Apple sauce and Toast.