You may experience nausea due to an infection, such as the stomach flu or food poisoning. It can also occur due to other health conditions, including food intolerances and heavy metal poisoning.

When your digestive system becomes irritated, or is exposed to something potentially damaging to your health, the nerves signal your system to expel its contents as quickly as possible. Vomiting, diarrhea, or both are the result.

These two symptoms often go together, and are typically linked to common conditions, such as a stomach virus or food poisoning.

Since diarrhea and vomiting are associated with many diagnoses, it may be hard to know what’s causing them. Here are some of the possible causes.

Viral gastroenteritis is a contagious, common condition caused by several different virus strains, such as the norovirus. Also known as the stomach flu, it’s not the same thing as the flu, which is a respiratory condition.

Viral gastroenteritis causes inflammation in the stomach and intestines. You can get it from close contact with people or contaminated surfaces.

Symptoms vary based on the underlying virus but typically include:

  • diarrhea
  • vomiting
  • achiness
  • fever
  • chills

Gastroenteritis usually clears up on its own within a few days. Treatment is centered on avoiding dehydration by sipping water or other fluids.

Food poisoning is caused by eating or drinking something contaminated with bacteria, a virus, or parasite. Mold and chemical or natural toxins can also cause food poisoning.

Millions of people come down with food poisoning annually in the United States. Symptoms include:

  • watery diarrhea
  • nausea
  • vomiting
  • stomach cramps

In most instances, these symptoms are mild and resolve on their own within one to two days. Food poisoning can, however, cause severe symptoms which require medical treatment.

If you’ve ever had a nervous stomach, you already know that strong emotion can affect your gut. Your digestive system can be adversely affected by fear, stress, or anxiety. It can cause diarrhea, vomiting, or dry heaving.

Powerful emotions trigger the fight-or-flight response. This puts your body on high alert, activating stress hormones, such as adrenaline and cortisol. These hormones signal your intestines to empty.

They also divert blood away from your stomach to the vital organs you may need most in an emergency, and cause abdominal muscles to clench. All of these physical reactions can bring on diarrhea or vomiting.

Reducing stress with deep breathing exercises and addressing anxiety with a mental health professional can help.

Cyclic vomiting syndrome is earmarked by episodes of severe vomiting that have no obvious cause. These episodes can last for hours or even days.

They often start at the same time of day, last for the same amount of time, and are uniform in severity. These episodes may be interspersed with periods of time when no vomiting occurs.

Other symptoms can include:

  • diarrhea
  • intense sweating
  • retching
  • severe nausea

The cause of cyclic vomiting syndrome is unknown, but stress or a family history of migraine may be a factor, especially in children.

Some triggers for this condition include caffeine, cheese, or chocolate. Avoiding these foods may help reduce or eliminate attacks.

A change in environment, especially to a place with less-than-optimal sanitary conditions, may result in traveler’s diarrhea. This condition is caused by eating or drinking something unclean or contaminated. Symptoms include:

  • diarrhea
  • stomach cramps
  • nausea
  • vomiting

Traveler’s diarrhea usually clears up on its own once you’re no longer eating or drinking the contaminated items. See your doctor to identify the bacteria or organism that is causing the diarrhea if:

  • it persists for more than a few days
  • it’s accompanied by severe dehydration
  • you have bloody or severe diarrhea
  • you have persistent vomiting

Over-the-counter anti-diarrheal medications can help. In some instances, prescribed medications may be necessary.

Motion sickness can happen at any age. It can be triggered by traveling in a car, boat, airplane or other vehicle.

Motion sickness happens when the central nervous system receives conflicting information from the inner ear and other sensory systems about your body’s flow of movement. That’s why turning your head or body in a moving vehicle can instigate an episode of motion sickness.

Symptoms include:

  • feeling queasy
  • breaking out in cold sweats
  • getting urgent diarrhea
  • vomiting

There are medications you can take prior to traveling which may help you avoid motion sickness. A few home remedies include:

  • resting
  • chewing gum
  • drinking ginger ale
  • taking a ginger supplement

Motion sickness usually dissipates within several hours.

Digestive issues are common occurrences during pregnancy. These include:

  • nausea
  • vomiting
  • diarrhea
  • constipation

Nausea and vomiting often occur during the first 16 weeks, when hormonal changes are taking place. It helps if you avoid strong-smelling foods and eat small, frequent meals.

Severe, unending nausea and vomiting during pregnancy may be caused by an uncommon disorder called hyperemesis gravidarum.

If diarrhea is accompanied by vaginal discharge and low back pain, let your doctor know immediately. Sometimes this triad of symptoms means you’re going into preterm labor.

Some prescription medications may cause vomiting and diarrhea as side effects. These include some antibiotics. Antibiotic-associated diarrhea may cause:

  • loose stool
  • frequent bowel movements
  • nausea
  • vomiting

These symptoms can occur a week or longer after you start taking the medication, and may last for weeks after you’ve stopped. Other prescribed medications can also cause these symptoms to occur.

Check the labels of your prescription medications to see if vomiting and diarrhea are listed. If so, make sure to stay hydrated if you experience these symptoms, and talk to your doctor about strategies for alleviating discomfort.

Taking antibiotics may also result in a C. difficile infection. C. diff is a type of bacteria which produces toxins that can cause antibiotic-associated colitis.

This can happen if antibiotic therapy throws off the balance of good and bad bacteria in your intestinal tract. Coming into contact with fecal matter or a contaminated surface can also cause a C. diff infection.

Common symptoms include:

  • mild-to-severe vomiting
  • diarrhea
  • cramping
  • low-grade fever

People with weakened immune systems and older individuals may be more susceptible to this type of infection. If you suspect that you have a C. diff infection, let your doctor know.

Heavy metal poisoning is caused by the accumulation of toxic amounts of heavy metals in the body’s soft tissue. Heavy metals include:

  • arsenic
  • lead
  • mercury
  • cadmium

Heavy metal poisoning can be caused by:

  • industrial exposure
  • pollution
  • medicines
  • contaminated food
  • exported good
  • other substances

Symptoms vary based on the toxin. They include:

  • diarrhea
  • nausea
  • vomiting
  • muscles weakness
  • abdominal pain
  • muscle spasms

Lead poisoning is most common in children between 1 and 3 years old. If you suspect heavy metal poisoning, your doctor will run tests and try to identify the toxin so you can eliminate it from your environment.

Other treatments, such as taking a chelating medication or having your stomach pumped, may also be needed.

Overeating can be taxing on the digestive system. This may be more likely to occur if you eat quickly, or if you eat fatty or spicy food. Symptoms include:

  • diarrhea
  • indigestion
  • nausea
  • feeling overly full
  • vomiting

Eating too much fiber can also cause these symptoms to occur, especially if you don’t typically eat a high-fiber diet.

Alcoholic beverages cause your stomach to secrete acid. Drinking to excess can cause inflammation in the stomach and digestive symptoms, such as nausea, vomiting, and diarrhea. Drinking less alcohol and watering down alcoholic drinks with mixers can help.

Crohn’s disease is a chronic type of inflammatory bowel disease. Its cause is unknown. There are several kinds of Crohn’s disease. Symptoms include:

  • stomach pain
  • diarrhea, which may be bloody
  • excessive vomiting
  • chills
  • fever
  • feeling faint

These symptoms can be signals that your condition is worsening or requires medical attention.

Crohn’s disease is typically treated with prescription medications. You may also feel relief from taking over-the-counter anti-diarrheal drugs. Smoking cigarettes makes Crohn’s symptoms worse and should be avoided.

Colon cancer, lymphoma, pancreatic cancer, and some other types may cause gastric symptoms such as diarrhea, vomiting, or constipation. Some forms of cancer may go undiagnosed until gastric symptoms occur.

Cancer treatments, such as chemotherapy, can also cause vomiting, nausea, and diarrhea. Let your doctor know if your symptoms are accompanied by:

  • pain
  • fever
  • dizziness
  • weight loss

There are medications and lifestyle changes that can help you alleviate nausea and other symptoms.

IBS is also known as spastic colon. It’s more common in women than in men. Symptoms can vary in intensity. They include:

  • diarrhea
  • constipation
  • vomiting
  • bloating
  • stomach pain

IBS can be a chronic, long-lasting condition. There is no cure, but dietary changes and medication can help.

A peptic ulcer is an open sore which develops somewhere in the digestive system, such as in the stomach lining or lower esophagus. Drinking too much alcohol, cigarette smoking, and exposure to H. pylori bacteria are some potential causes.

Abdominal pain is the main symptom of a peptic ulcer. Other symptoms include:

  • watery diarrhea
  • vomiting
  • nausea
  • indigestion
  • blood in the stool

Treatment may include lifestyle changes, antibiotics, and acid blockers.

Some people have trouble digesting lactose, a type of sugar found in milk and dairy products. This condition is more common in adults than it is in children. Lactose malabsorption can cause symptoms such as:

  • gas
  • bloating
  • vomiting
  • nausea
  • diarrhea

Your doctor can diagnose lactose intolerance with a hydrogen breath test. Avoiding foods containing lactose is the best way to avoid symptoms.

Abdominal migraine is a subtype of migraine which includes diarrhea as a symptom. This condition can be debilitating. With abdominal migraine, the pain is centered in the stomach instead of in the head. Regular migraine attacks can also have diarrhea and vomiting as symptoms.

Migraine is more common in women than it is in men. Some women notice a pattern between their menstrual cycle and migraine. Migraine may also have a genetic link. Some people find relief by identifying and eliminating triggers in their environment.

This rare condition is caused by long-term, heavy use of THC-rich marijuana. Symptoms include:

  • nausea
  • vomiting
  • abdominal pain
  • diarrhea

It causes a compulsion to bathe in hot water. If you suspect that you have this condition, eliminating marijuana use can help. You can also talk to your doctor or healthcare provider about lifestyle interventions which can help you to avoid this condition in the future.

A bowel obstruction is a potentially dangerous condition, caused by a blockage in the large or small intestine. Vomiting and diarrhea are early warning signs for this condition. Bloating, constipation, and cramping can also be symptoms.

There are many causes for this condition. They include impacted stool, postsurgical adhesions, and tumors. A bowel obstruction requires medical care. Treatments range from medication to therapeutic enemas or surgery.

While we’ve already discussed treatment for each condition, a few home remedies can also help reduce diarrhea and vomiting symptoms, including:

  • Rest. Your body needs a chance to fight off the cause of your symptoms. Letting yourself rest can help alleviate the dizziness caused from motion sickness, too.
  • Hydration. Dehydration occurs when you lose more fluid than you’re taking in. Dehydration can be dangerous, especially for infants, children, and older adults. Slowly sipping water, broth, or sports drinks that replace electrolytes can all help you to avoid dehydration. If you can’t keep liquids down, try sucking on ice chips or ice pops.
  • Eat lightly. Once your appetite returns, eat sparsely and avoid spicy or fatty foods. Some people have trouble tolerating dairy but others can tolerate cottage cheese. Bland foods you may want to try include:
    • soft-boiled eggs
    • toast
    • bananas
    • apple sauce
    • crackers
  • Medications. Avoid pain medications, such as ibuprofen, that may irritate the stomach. Over-the-counter anti-diarrheal medications can help with diarrhea, and anti-nausea medications can also help reduce queasiness.

Since diarrhea and vomiting can have many causes, it’s important to seek medical help if your symptoms don’t improve or worsen. Those who should always see a doctor for chronic diarrhea and vomiting include:

  • infants
  • toddlers
  • children
  • older adults
  • those with compromised immune systems

Anyone should check in with their doctor if they have:

  • diarrhea that’s bloody or lasts longer than three days
  • uncontrollable vomiting or retching, which makes it impossible to keep down fluids for more than one day
  • symptoms of dehydration, including:
    • light-headedness
    • sunken eyes
    • crying without tears
    • inability to perspire or urinate
    • very dark urine
    • muscle cramps
    • dizziness
    • weakness
    • confusion
    • fever over 102°F (38.9°C)
    • extreme pain or muscle cramping
    • uncontrollable chills

Nausea and diarrhea can be caused by a wide range of conditions but are most often linked to viral infections or food poisoning.

These symptoms often respond well to at-home treatments. If your symptoms last longer than a few days or are severe, check in with your doctor.