Reheated rice syndrome, or fried rice syndrome, is food poisoning caused by the Bacillus cereus (B. cereus) bacterium. Symptoms can include vomiting and diarrhea.

Reheated rice syndrome can happen if you reheat and then eat rice that was previously not stored correctly. It will typically resolve within 24 hours, and home remedies can help manage symptoms.

Read on to learn more about the symptoms and causes of reheated rice syndrome. This article also looks at how doctors confirm the condition, what treatments may help, and more.

The Bacillus cereus bacterium can cause two types of syndromes: diarrheal syndrome and emetic syndrome. This means it can cause diarrhea or vomiting.

Diarrhea-type reheated rice syndrome is likely to cause:

Emetic-type reheated rice syndrome is likely to cause:

Symptoms of both types will typically resolve within 24 hours.

How quickly do symptoms appear?

Symptoms of diarrheal reheated rice syndrome usually occur within 6 to 15 hours after consuming the rice.

Symptoms of emetic reheated rice syndrome typically begin within 30 minutes to 6 hours.

Reheated rice syndrome can happen after eating previously heated rice that has been sitting out at room temperature for more than 2 hours.

As the name suggests, symptoms can develop even after reheating the rice.

B. cereus can multiply in conditions below 4ºC (39.2ºF). As the B. cereus spores can survive cooking, reheating the rice does not kill the bacteria.

As reheated rice syndrome typically resolves on its own, a diagnosis may not be necessary.

However, a doctor may decide to test stool or vomit samples to confirm the presence of B. cereus or rule out other possible causes.

Symptoms of reheated rice syndrome will usually resolve within 24 hours without medical treatment.

To help ease symptoms and feel more comfortable, it’s important to get plenty of rest and drink enough fluids.

In severe cases, you may require intravenous (IV) fluid to prevent dehydration.

The best way to reduce the risk of reheated rice syndrome is to properly store rice that’s been cooked and eat it within a short time frame.

The United Kingdom’s Food Standards Agency suggests that it may be OK to eat rice leftovers within 24 hours if they cool down quickly and are then refrigerated, ideally within 1 hour.

Only reheat the rice once and make sure the rice is steaming hot all the way through.

Contact a doctor if symptoms last more than 24 hours. Your doctor can advise on treatments that may help. They may also want to order tests to rule out other causes of vomiting or diarrhea.

You should also get medical advice if you are unable to drink enough fluids to stay hydrated. It may be necessary to receive IV fluids.

Reheated rice syndrome, also known as fried rice syndrome, is a type of food poisoning that causes vomiting or diarrhea.

It typically happens when the Bacillus cereus bacterium multiplies in cooked rice that has been left out at room temperature. Refrigerating rice within an hour of it cooling down and then consuming it within 24 hours may help minimize this risk. Reheating the rice does not kill the bacteria spores.

Symptoms of reheated rice syndrome typically resolve within 24 hours. Getting rest and drinking plenty of fluids can help. While medical treatment is not usually necessary, a doctor may recommend IV fluids if there is a risk of dehydration.