Food poisoning is a common illness that happens when you eat or drink something contaminated with germs or toxins. It’s important to recognize the signs of food poisoning so you can take care of yourself and know when to seek medical help. Knowing what to look for can help you differentiate food poisoning from other illnesses and take appropriate action.
The symptoms of food poisoning can vary, but some are more common than others. Typically, the first signs involve your digestive system. You might experience an upset stomach, feeling queasy and uncomfortable. This often progresses to nausea, the sensation that you’re about to vomit. Vomiting itself is a frequent symptom, as your body tries to expel the harmful substances.
Diarrhea is another very common symptom. This can range from mild to severe, and in some cases, it may even include bloody stools. You may also experience stomach pain and cramps, which can be quite uncomfortable. In addition to these digestive issues, you might develop a fever and a headache. These are general signs of illness that often accompany food poisoning as your body fights off the infection.
While the symptoms mentioned above are the most common, food poisoning can sometimes present with more serious, though less frequent, symptoms. These symptoms often indicate that the food poisoning is affecting your nervous system and require immediate medical attention. One alarming symptom is blurred or double vision. Headaches, beyond a typical headache, can also be a sign of a more severe reaction.
Loss of muscle control, such as weakness in your limbs or difficulty moving them, is another serious symptom. Problems with swallowing, tingling or numbness of the skin, and changes in your voice can also occur. These neurological symptoms suggest a more severe form of food poisoning that needs prompt medical evaluation.
The timing of your symptoms can also be a clue that you have food poisoning. Symptoms can appear quickly, sometimes within just 30 minutes of eating contaminated food, or they might take longer, even up to a few weeks, depending on the specific cause of the illness. For example, illnesses caused by bacteria like Bacillus cereus or Staphylococcus aureus can cause symptoms within hours, while infections like Hepatitis A can take weeks to manifest. The table below provides a guide to the typical timing of symptoms for different causes of foodborne illnesses:
| Disease cause | Timing of symptoms | Common sources |
|---|---|---|
| Bacillus cereus (bacterium) | 30 minutes to 15 hours. | Foods such as rice, leftovers, sauces, soups, meats and others that have sat out at room temperature too long. |
| Campylobacter (bacterium) | 2 to 5 days. | Raw or undercooked poultry, shellfish, unpasteurized milk, and contaminated water. |
| Clostridium botulinum (bacterium) | 18 to 36 hours. Infants: 3 to 30 days. | For infants, honey or pacifiers dipped in honey. Home-preserved foods including canned foods, fermented fish, fermented beans and alcohol. Commercial canned foods and oils infused with herbs. |
| Clostridium perfringens (bacterium) | 6 to 24 hours. | Meats, poultry, stews and gravies. Commonly, food that is not kept hot enough when served to a large group. Food left out at room temperature too long. |
| Escherichia coli, commonly called E. coli (bacterium) | Usually, 3 to 4 days. Possibly, 1 to 10 days. | Raw or undercooked meat, unpasteurized milk or juice, soft cheeses from unpasteurized milk, and fresh fruits and vegetables. Contaminated water. Feces of people with E. coli. |
| Giardia lamblia (parasite) | 1 to 2 weeks. | Food and water contaminated with feces that carry the parasite. Food handlers who are carriers of the parasite. |
| Hepatitis A (virus) | 15 to 50 days. | Raw and undercooked shellfish, fresh fruits and vegetables, and other uncooked food. Food and water contaminated with human feces. Food handlers who have hepatitis A. |
| Listeria (bacterium) | 9 to 48 hours for digestive disease. 1 to 4 weeks for body-wide disease. | Hot dogs, luncheon meats, unpasteurized milk, soft cheeses from unpasteurized milk, refrigerated smoked fish, refrigerated pates or meat spreads, and fresh fruits and vegetables. |
| Norovirus (virus) | 12 to 48 hours. | Shellfish and fresh fruits and vegetables. Ready-to-eat foods, such as salads and sandwiches, touched by food handlers with the virus. Food or water contaminated with vomit or feces of a person with the virus. |
| Rotavirus (virus) | 18 to 36 hours. | Food, water or objects, such as faucet handles or utensils, contaminated with the virus. |
| Salmonella (bacterium) | 6 hours to 6 days. | Most often poultry, eggs and dairy products. Other foods such as fresh fruits and vegetables, meat, poultry, nuts, nut products, and spices. |
| Shellfish poisoning (toxin) | Usually 30 to 60 minutes, up to 24 hours. | Shellfish, including cooked shellfish, from coastal seawater contaminated with toxins. |
| Shigella (bacterium) | Usually, 1 to 2 days. Up to 7 days. | Contact with a person who is sick. Food or water contaminated with human feces. Often ready-to-eat food handled by a food worker with shigella. |
| Staphylococcus aureus (bacterium) | 30 minutes to 8 hours. | Meat, egg salad, potato salad or cream-filled pastries that have been left out too long or not refrigerated. Foods handled by a person with the bacteria, which is often found on skin. |
| Vibrio (bacterium) | 2 to 48 hours. | Raw or undercooked fish or shellfish, especially oysters. Water contaminated with sewage. Rice, millet, fresh fruits and vegetables. |
Knowing when to seek medical attention is crucial. For infants and children, dehydration is a significant concern because they can become dehydrated very quickly due to vomiting and diarrhea. If your child has these symptoms along with unusual behavior changes, excessive thirst, reduced urination, weakness, dizziness, diarrhea lasting more than a day, frequent vomiting, bloody or black stools, severe stomach pain, fever (especially in young children), or has a history of medical problems, it’s important to call their doctor immediately.
Adults also need to be aware of when their symptoms warrant medical help. If you experience nervous system symptoms like blurred vision, muscle weakness, or tingling, seek immediate medical care. Changes in thinking or behavior, a high fever (103°F or 39.4°C or higher), frequent vomiting, diarrhea lasting more than three days, or signs of dehydration (extreme thirst, dry mouth, reduced urination, severe weakness, dizziness) are all reasons to consult a healthcare provider or seek emergency care.
Food poisoning is caused by consuming food or drinks contaminated with harmful substances. These contaminants can include bacteria, viruses, parasites, and toxins. Food can become contaminated at any stage, from production and processing to preparation and serving. Poor handwashing, unsanitized cooking areas, and improper food storage are common ways food gets contaminated, even at home.
Anyone can get food poisoning, but certain groups are at higher risk of developing severe illness or complications. These include infants and young children, pregnant women, older adults, and people with weakened immune systems due to underlying health conditions or medical treatments. For these vulnerable populations, taking extra precautions to prevent food poisoning is especially important.
While most cases of food poisoning are mild and resolve on their own, complications can occur, especially in high-risk individuals. Dehydration is the most common complication, resulting from fluid loss due to vomiting and diarrhea. Severe dehydration can lead to organ damage and can be life-threatening if left untreated.
In some cases, food poisoning can lead to more serious systemic complications, where the infection spreads beyond the digestive system. These complications can include kidney problems, blood infections, meningitis, and sepsis. Pregnant women who get food poisoning from Listeria bacteria are at risk of miscarriage, stillbirth, and severe infections in their newborns. Rarely, long-term conditions like arthritis, irritable bowel syndrome, and Guillain-Barre syndrome can develop after food poisoning.
Preventing food poisoning is always better than treating it. Good hygiene practices in the kitchen are essential. Wash your hands thoroughly with soap and water for at least 20 seconds before and after handling food, and especially after using the restroom. Rinse fruits and vegetables well under running water. Clean kitchen utensils and surfaces, especially cutting boards and knives, with soapy water after they come into contact with raw meat or unwashed produce.
Cook meat, poultry, and fish to safe internal temperatures. Use a food thermometer to ensure accuracy. Refrigerate leftovers promptly after meals and consume them within 3-4 days. If you’re unsure about the safety of any food, it’s best to discard it. Be careful with moldy food; while you can sometimes trim mold from firm produce, it’s generally safer to throw away moldy items, especially soft fruits, vegetables, and baked goods. Regularly clean your refrigerator to prevent the growth and spread of bacteria and mold.
By being aware of the symptoms of food poisoning, understanding the potential causes and risks, and practicing safe food handling at home, you can significantly reduce your chances of getting sick and protect your health. If you suspect you have food poisoning, pay close attention to your symptoms and seek medical advice when necessary.
