Food poisoning is a medical condition that is caused by the consumption of food that has been contaminated by bacteria or toxins. Side effects of food poisoning generally arise within 2 to 6 hours following consumption of the contaminated food, explain health professionals at Medline Plus, an online medical encyclopedia provided as a service of the U.S. National Library of Medicine. Typically, food poisoning is the result of ingesting food that has been undercooked, poorly handled or stored improperly.
Nausea and vomiting are the predominate side effects associated with food poisoning. When toxic bacteria enter your body through your digestive tract, your immune system causes you to experience nausea and vomiting in an attempt to expel the toxin from your body. Depending upon the type of toxin and the amount of contaminated food you ingest, side effects of nausea and vomiting can be mild to severe. Typically, these symptoms last for approximately 12 to 48 hours, explains Medline Plus. If such side effects persist longer than 48 hours, contact your primary care physician immediately for further care.
After ingesting contaminated food products, you can experience mild to severe diarrhea as a side effect of this condition. Diarrhea causes frequent bowel movements that result in loose or watery stools. If you develop diarrhea as a side effect of food poisoning, you can also experience abdominal bloating, cramping or discomfort due to this condition. Diarrhea can also cause dehydration—a condition that results from abnormally low levels of fluid within the body. If you develop dehydration due to diarrhea caused by food poisoning, you may also experience headache, lightheadedness, fatigue or increased thirst.
If you ingest food that has been contaminated by a bacterial or viral toxin, you can experience fever as a side effect of this condition. An elevated body temperature is an immune defense utilized by your body to prevent bacteria or viruses from replicating and spreading throughout your body. Fever due to food poisoning is typically low-grade and resolves once the bacteria or virus has been cleared from your body.
You can develop a headache as a side effect of food poisoning. Headache pain is typically mild to moderate in severity and is often accompanied by additional side effects, such as nausea, vomiting, diarrhea or fever. Headache symptoms can also arise due to dehydration caused by bacteria or virus-induced diarrhea. Drinking small amounts of fluid while you are experiencing food poisoning side effects can help alleviate headache symptoms in certain people.