Vomiting and Diarrhea: What Are the Causes and Treatments?

No one likes dealing with an upset stomach. Whether it is caused by a virus you picked up, strenuous exercise, or something you ate, you probably feel miserable.

Fortunately, if you’re struggling with a mild case of vomiting and diarrhea, it’s likely to be short-lived and nothing serious. Here we take you through the possible causes of stomach upset as well as some preventative measures including what foods to eat and when to call a doctor.

Possible Causes

There are a variety of different causes for vomiting and diarrhea including everything from eating a bad plate of food to participating in strenuous endurance exercises. What's more, the likelihood of experiencing these symptoms is higher with heat, stress, or dehydration.

To prevent vomiting and diarrhea, you should refrain from eating before exercise, stay hydrated, and take breaks when you need them. Here's more about why your stomach may be upset.

Symptoms After Eating

If you are experiencing GI symptoms after eating, it could be that your food didn’t digest well or that you have a food intolerance or even a food allergy. If you have an allergy or intolerance to a particular food, you will experience these symptoms nearly every time you eat the offending food.

Some people find that keeping a log is helpful in trying to pinpoint food intolerances. Record what you ate and your symptoms. You also should work with a doctor or a dietician if you suspect that your symptoms are caused by food intolerances.

If your stomach upset isn't caused by food intolerances, there are some other possible causes for your vomiting and diarrhea after eating. These possibilities include food poisoning and gastroenteritis, both of which can be caused by bacteria or a virus. These conditions usually cause abdominal cramping, nausea, vomiting, fever, and diarrhea.

Gastroenteritis is the most common cause of vomiting and diarrhea according to Brynna Connor, MD, healthcare ambassador at NorthWestPharmacy.com. If you have gastroenteritis, there is a chance you are contagious.

To be safe, you should probably stay home until symptoms subside. You can work out again in a few days, as long as your symptoms have stopped for at least 48 hours and you are properly hydrated.

Meanwhile, food poisoning symptoms can be anywhere from mild to very serious depending on what germ caused your illness. If you develop a fever over 102, have bloody diarrhea, diarrhea that lasts more than 3 days, or signs of dehydration you should talk to a healthcare professional.

Symptoms After Exercise or Strenuous Activity

If you are experiencing vomiting and diarrhea after exercising or strenuous activity, there are many possible causes with the most common cause being dehydration. If you are dehydrated or have been out in the sun for a long time, you should go inside and drink water.

Heatstroke can cause gastrointestinal (GI) symptoms, and you are more susceptible to this condition if you are dehydrated. If this is the case, you should be careful about prolonged sun exposure in the future.

What's more, these symptoms seem to impact endurance athletes the most with nearly 85% of marathon runners reporting a link between GI symptoms and running.

Overall, there could be several reasons for exercise-induced nausea and GI symptoms. At the top of the list is reduced blood flow to the digestive tract and abdominal organs.

Other possible causes include dehydration, delayed gastric emptying, and hyponatremia, which is a lack of sodium in the blood. Additionally, if you eat directly before working out, it is possible that the flow of blood toward your muscles—and away from your stomach—will cause digestion issues.

Typically, GI symptoms are likely to occur after at least 2 hours of continuous endurance exercise. If you experience continued GI symptoms every time you exercise, you should talk to a healthcare provider.

Other Possible Causes

GI symptoms can also simply be caused by a hangover or anxiety. If you drank alcohol the night before, be sure to drink lots of water. Hangovers generally do not last more than a day.

And if you are dealing with anxiety, depression, or another mental health issue that could be causing your stomach upset, talk to a healthcare professional. They can help you develop a treatment plan that helps you manage your symptoms.

Recurring GI symptoms with no known cause could be a sign of irritable bowel syndrome (IBS). IBS is a medical condition that affects digestion because the food will often not digest properly or easily.

How to Prevent Vomiting and Diarrhea

Sometimes vomiting and diarrhea are unavoidable especially if you have a virus or have developed a case of food poisoning. But, there are things you can do to try to keep stomach upset at bay.

For instance, you could avoid eating within 2 hours of working out. Eating before a workout can cause your body to direct its attention away from digestion and toward your muscles, leaving you with GI symptoms such as vomiting and diarrhea. 

Instead, take small sips of water or drink something with electrolytes in it when you work out. And, when you're not working out, focus on staying hydrated because dehydration alone can cause GI symptoms. Dehydration also can leave you susceptible to getting heat stroke more quickly as well.

Considering that GI symptoms are most common in endurance athletes, there are a few other considerations for preventing exercise-induced vomiting and diarrhea. For instance, the intake of sodium and carbohydrates, which are found in most sports drinks, can assist with the absorption of the water you do drink. For this reason, you should drink half a liter of a sports drink per hour during intense exercise.

What Foods Can Settle Your Stomach?

When you are plagued with stomach upset, the best course of action is to get plenty of rest, stay hydrated, and avoid stress. You should also limit your diet to bland foods in an attempt not to upset your stomach further. Try to stick to bland foods until your symptoms have stopped for 12 to 48 hours.

When to See a Doctor

If you are plagued by vomiting and diarrhea on a consistent basis, you should speak to a healthcare provider. In addition to viruses, food poisoning, and exercise-induced GI symptoms, there are more serious medical issues that could be causing your stomach upset.

“[In general], you should see a physician when the vomiting and diarrhea do not resolve after 48 hours," says Dr. Connor. "However, it really depends on the person‘s individual health history as some might need medical attention sooner than that two-day mark.”

For instance, if you take any medication and your symptoms are not allowing you to keep it down, you should contact a healthcare provider right away. You also should get immediate medical care if your stool is black, bloody, or contains pus.

Likewise, be on the lookout for symptoms of dehydration which include experiencing dry mouth or tongue, having less urine output, feeling faint, being thirsty, having a headache, feeling lethargic, or even having a higher temperature. After all, the most common side effect of GI symptoms is dehydration, which sometimes can require immediate medical care.

A Word From Verywell

It is not uncommon for people to experience vomiting and diarrhea—especially during cold and flu season when viruses are more prevalent. That said, there are other causes of vomiting and diarrhea worth noting such as food poisoning, gastroenteritis, and even exercise-induced GI symptoms.

If you are experiencing stomach upset that is causing you to be nauseous, vomit, and experience diarrhea, try to rest, eat and bland diet, and stay hydrated. Usually, these symptoms will pass in a few days. However, if you are still experiencing issues after 48 hours, or if you show signs of dehydration, it's important to contact a healthcare provider right away.