You'll want to let the doctor know what's going on as soon as you suspect your child might have food poisoning. She can decide if your child's symptoms warrant an office visit. Tell the doctor about any of the following signs:
Also call your doctor if your child shows any of the classic signs of dehydration, including decreased urination, excessive sleepiness or fussiness, cool and discolored hands and feet, or extreme thirst. If this happens, your child's doctor might want to admit him to the hospital (or just keep him there for a few hours) for IV rehydration. Don't be alarmed. Odds are, he'll be released and back to his healthy self within a few days' time.
If you're concerned that your child may have food poisoning and your doctor isn't available, speak to the doctor on call or take your child to the emergency room.
If your preschooler is having trouble breathing or swallowing, or shows any signs of severe dehydration, call 911.
Assuming your child has a run-of-the-mill case of food poisoning, with vomiting or diarrhea, you'll want to keep him home to rest and replace the lost fluids and electrolytes (salt and minerals) that his body is losing. Usually, doctors recommend giving an over-the-counter oral electrolyte solution, such as Equalyte or Pedialyte (which is also sold as ice pops), by offering small sips frequently throughout the day. Your doctor can tell you how much your child needs to be drinking based on his age and weight. (Avoid juices and sodas, though, because these may make his symptoms worse.)
If your child has a fever or is achy, you can give him the proper dose of children's acetaminophen or ibuprofen. Never give your child aspirin as it makes him more susceptible to Reye's syndrome, a rare but potentially fatal disease.