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Food Poisoning


Food poisoning occurs after eating food that contains harmful microorganisms or toxins. It is also known as foodborne illness. Improper handling of food substances or working in unsanitary conditions can increase the risk of food poisoning. The majority of the cases of food poisoning are mild to moderate and get resolved on their own. However, some people might experience severe symptoms for more than a few days. In such cases, emergency medical care should be given. According to CDC, almost one in every seven persons is affected by food poisoning once a year in the United States.


Food poisoning can be caused by various bacteria, viruses, or parasites. These pathogens are present in edible substances. When you cook food, most of these pathogens are killed by that high temperature. Eating raw food is one of the most common reasons for food poisoning.

Some common examples of bacterial food poisoning include E.coli, Salmonella, Campylobacter, Clostridium botulinum, Listeria monocytogenes, Staphylococcus aureus, etc. Salmonella is considered one of the most significant causes of food poisoning in the United States. The major source of this bacteria is raw, contaminated meat, eggs, milk, or poultry.

Viruses involved in food poisoning include norovirus, rotavirus, hepatitis A virus, astrovirus, sapovirus, etc. The most common cause among these is norovirus. According to CDC, around 19 to 21 million cases of norovirus infection are reported each year in the United States.


Some common parasites that can cause food poisoning include Toxoplasma gondii, Giardia lamblia, Ascaris lumbricoides, and various tapeworms. These parasites enter your system via food. In certain cases, they can live and replicate in your system for years without any noticeable symptoms. 

Risk Factors And Epidemiology

Although anyone can get food poisoning after eating contaminated food, the severity of symptoms may vary depending on certain factors. Children and older adults are at high risk of getting food poisoning because their immune systems are weaker compared to adults. Similarly, pregnant women are also at higher risk due to changes in their metabolism. In some cases, the fetus may get affected as well. Patients with immunocompromising diseases, taking immunosuppressant medications or undergoing chemotherapy or radiotherapy have a greater risk of getting infected.


On a global scale, food poisoning has lessened compared to the previous decade due to advanced sanitary measures. However, around 325,000 hospitalizations are reported in the United States yearly. Most of these patients survive, but some cases with severe symptoms lead to life-threatening complications. 

Signs And Symptoms

Common symptoms of food poisoning include nausea, vomiting, abdominal pain, and diarrhea. You may also develop fever in certain cases. Because of nausea and vomiting, your appetite gets affected as well. Weakness, lethargy, and dizziness are possible if you have expelled more food than you have eaten. If you develop diarrhea for more than three days, high-grade fever, blood in stool or vomit, or signs of dehydration, contact a doctor immediately to receive treatment. 


Food poisoning is usually diagnosed on the basis of its symptoms. Your doctor will inquire about your recent meals, the severity of your symptoms, and medical history to suspect a possible cause. In certain cases, blood tests, culture tests, or stool test is required to diagnose the offending pathogen. 

Differential Diagnosis

Many diseases can present with similar symptoms as food poisoning. Some of them include hepatitis, jaundice, gastritis, gastroenteritis (stomach flu) and other gastrointestinal infections. These symptoms can also occur due to a side effect of a medicine or as an allergic reaction to certain food substances. 


Treatment of food poisoning depends on its cause. Mild food poisoning does not require any treatment except for symptomatic care. The basic treatment measure is to replenish the fluids lost from your body in the form of vomiting or diarrhea. These fluids can be given orally or intravenously. If you are unable to eat, you will be kept on a liquid diet for a few days. Avoid eating food from outside until you have recovered. Bed rest and adequate hydration levels are the primary measures to recover from food poisoning.

Medicines are not recommended for mild to moderate food poisoning. The only medication given is those to lessen your symptoms. For example, an antipyretic will be given for fever, or an analgesic such as ibuprofen, diclofenac, etc., will be given for abdominal pain.


If you have been diagnosed with bacterial food poisoning, your doctor may prescribe a dose of antibiotics to kill the particular bacteria. Remember that antibiotics will not help with viral or parasitic food poisoning. Do not take any medicine without consultation from your healthcare provider. 


Many people recover from food poisoning within one to two days. Those with severe food poisoning may take longer than a week to recover. In rare cases, excessive dehydration and severe symptoms may lead to mortality. 


Food poisoning can be prevented by practicing food safety and sanitary measures. Before cooking a meal, wash your hands and clean all the raw ingredients. Meat, fish, fruits, vegetables, etc., that are bought from open stores should be thoroughly washed before use. Refrigerate food items that need to be kept at a freezing temperature if you plan to use them later. Cook your food at an optimum temperature to ensure that majority of the pathogens are killed before you consume it. Take extra precautions with ingredients if you have a weakened immune system.

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 19, 2023.



Food Poisoning Symptoms | CDC


Food Poisoning - NIDDK (nih.gov)