Morning diarrhea is when a person passes a loose or watery stool first thing in the morning. Potential causes include alcohol or caffeine, temporary illness, certain medications, stress, or a chronic condition.

Many people experience diarrhea at some point. Occasional morning diarrhea may not be a sign of anything serious. It could result from lifestyle choices or a short-term virus, such as stomach flu.

However, having morning diarrhea on a regular basis may be a sign of an underlying condition that requires medical treatment.

Read on to learn more about what might cause diarrhea in the morning.

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Diarrhea in the morning may occur due to:

Caffeine or alcohol

Caffeine is a stimulant and speeds up bowel movements. Drinking many caffeinated beverages, such as coffee or tea, may cause diarrhea.

Alcohol can also cause loose stools. Drinking in the evening may lead to hangover symptoms — including diarrhea — the following morning.


Laxatives are medications that increase bowel movements. People take them to help treat constipation, but some also misuse them in an attempt to lose weight, which is unsafe.

Taking a laxative before bed may result in diarrhea in the morning. Some foods can have a similar effect when a person eats them in high enough quantities. This includes foods that are high in polyols, such as:

  • some fruits, including prunes, apricots, and pears
  • sugar-free mints, chewing gum, or candies
  • low calorie sweeteners
  • cough syrups or lozenges


In addition to laxatives, many other medications can also cause diarrhea as a side effect. This includes, but is not limited to:

The diarrhea may stop when treatment is over or a person stops the medication, but it is important not to change any medications without a doctor’s supervision.


An infection may cause diarrhea in the morning, which may continue throughout the day. Many types of infection can cause diarrhea, including:

These infections may also cause:

Minor stomach bugs can resolve on their own, but others may require medical treatment.


Although constipation is more common in pregnancy, some people can experience diarrhea instead. A 2022 study states this may occur for several reasons, including:

  • hormonal changes
  • dietary changes
  • the side effects of prenatal vitamins
  • pre-existing conditions

Anyone who could be pregnant can test for this by purchasing an over-the-counter pregnancy test. Alternatively, they can ask a doctor.


For some people, stress or anxiety can trigger diarrhea. Digestive symptoms are a common physical symptom of mental health conditions. Other physical signs of stress may include:

Learn more about stress and how to manage it.

Irritable bowel syndrome (IBS)

IBS is a long-term condition that causes diarrhea, constipation, or both. Scientists do not fully understand the causes, but some people find that certain foods or stress can trigger symptoms.

In addition to diarrhea and constipation, IBS may cause:

  • bloating
  • gas
  • abdominal pain and cramping

People who have IBS and eat trigger foods in the evening may experience diarrhea overnight or the following morning.

Inflammatory bowel disease (IBD)

IBD is an umbrella term for various autoimmune conditions that cause inflammation in the gut, including Crohn’s disease and ulcerative colitis.

The symptoms of IBD can include:

  • diarrhea
  • mucus or blood in the stool
  • abdominal pain
  • bowel urgency

Learn more about IBD.

Food allergies or intolerances

People who eat foods they are allergic to may develop irritation of the gut, leading to morning diarrhea. Other potential symptoms of a food allergy include:

  • skin flushing
  • hives
  • runny or blocked nose
  • sneezing
  • nausea
  • abdominal pain
  • vomiting

Some of the most common food allergies include milk, nut, and egg allergies. A doctor can test for food allergies to determine what a person might be allergic to.

A similar possibility is a food intolerance. This is different from an allergy, but can also result in diarrhea because the body is unable to digest a particular food. Lactose intolerance is one example.

Treatment for morning diarrhea depends on the cause. Some causes may not need any treatment. Most cases of short-term diarrhea occur due to infections and often resolve on their own.

When morning diarrhea persists, it may help to address lifestyle factors that could be causing it. For example, people can try:

  • reducing caffeine intake
  • limiting alcohol
  • limiting consumption of foods high in polyols, such as xylitol and sorbitol
  • reducing stress

If this does not help, a person should seek advice from a doctor. They will be able to perform tests to identify the cause.

They can also assess the medications a person is taking to check whether they could be causing diarrhea and suggest alternatives.

Depending on test results, a doctor may suggest:

  • dietary changes to help avoid trigger foods or allergens
  • short-term medications that may stop or reduce diarrhea when it happens
  • long-term medications to help manage ongoing conditions, such as IBD

Sometimes, people with IBD can also require surgery.

Many factors can influence digestion, so what helps prevent morning diarrhea will depend on what is causing it. It may help to reduce:

  • caffeine
  • alcohol consumption
  • stress

People can also help reduce the risk of getting stomach infections or food poisoning by following safety guidelines. These include:

  • avoiding contact with people who are unwell with an infection
  • washing the hands with soap and water after using the bathroom, before and after handling food, and after contact with someone who is sick
  • using alcohol hand gel when soap and water are not available
  • preparing, cooking, and storing foods safely

Occasional or mild diarrhea usually does not cause complications. However, persistent diarrhea that results in the loss of fluids or nutrients can become serious. A person may develop:

Getting enough fluids and electrolytes is important during persistent diarrhea.

Some causes of morning diarrhea are temporary and may pass on their own. However, people should speak with a doctor if the diarrhea does not go away, is severe, or contains blood. This may make the stool red or tarry and black.

Seek immediate help if a person begins showing signs of significant dehydration. The symptoms include:

  • tiredness or lethargy
  • confusion
  • lack of urination
  • lack of saliva or tears
  • weak or rapid pulse
  • fast breathing
  • in babies, a sunken spot on the top of the head
  • difficulty staying awake
  • loss of consciousness

Occasional morning diarrhea may be caused by a minor, temporary condition, such as a stomach bug or food poisoning. It could also be due to drinking a lot of caffeine or consuming alcohol the night before.

If the diarrhea is more persistent, it may be the result of something a person is eating or could indicate a chronic condition. A doctor can evaluate the symptoms and run tests to identify the cause. They will also be able to recommend treatments.