Why You Keep Getting Diarrhea On, and Off: Possible causes, Doctor Explains.

Our content is not intended nor recommended as a substitute for medical advice by your doctor. Use for informational purposes only.

Summary of the possible causes of getting on and off diarrhea:

  • Irritable bowel syndrome.
  • Food intolerance.
  • Stress and anxiety.
  • Medications such as metformin, proton pump inhibitors, and laxative abuse.
  • Exagerated gastro-colic reflex.
  • Other causes such as Diabetes Mellitus, celiac disease, inflammatory bowel disease, endocrinal disease, some rare intestinal diseases, and colorectal cancer.

The details are explained below.

1. Food intolerance.

We define food intolerance as difficulty digesting or absorbing certain types of food. Food intolerance is shockingly common. According to research estimates, about 15-20% of people have some degree of food intolerance (reference).

Food intolerance is one of the important causes of getting intermittent diarrhea (on and off).

  • It is widespread.
  • Diarrhea is related to the ingestion of the offending food. So, diarrhea occurs intermittently (on and off) depending on what you eat.

You can develop intolerance either to one or multiple types of food. Here are some common examples:

1- Lactose intolerance (intolerance to milk and other dairy products.

2- Caffeine intolerance (in coffee, chocolate, etc.).

3- FODMAP intolerance (a group of short-chain carbohydrates that ferment rapidly inside your intestine and may cause random diarrhea). Most people with irritable bowel syndrome are intolerant to FODMAPs.

4- Fructose intolerance (present mainly in honey and fruits).

5- Gluten intolerance (celiac disease).

6- Other types of food intolerance, such as alcohol intolerance, amines, sulfites, eggs, etc.

Symptoms suggestive of food intolerance:

  • Diarrhea every time you eat the offending food (on and off diarrhea).
  • Abdominal colics (ramps).
  • Bloating and distension.
  • Gas and flatulence (farting too much).
  • Rarely it can cause constipation.
  • Nausea with or without vomiting may also occur randomly.
  • The symptoms start shortly after eating and may last for days.

Moreover, a food allergy is different from a food reaction. It also can cause attacks of diarrhea (on and off).

The table below summarizes the differences between food intolerance and food allergy.

Food intoleranceFood allergy
Affects 15-20% of the populationAffects nearly 2-5% of adults
Difficulty digesting certain types of food (not immune-mediated allergy).An immune-mediated reaction to certain foods or food components.
Diarrhea is often random (you will get diarrhea every time you eat the offending food).Usually causes acute attacks related to the ingestion of offending food.
Intestinal symptoms: diarrhea, extensive gas, bloating, and abdominal painIntestinal symptoms are the same
No extraintestinal symptomsExtraintestinal symptoms include rashes, urticaria, swollen lips, face, or life-threatening allergic reactions.
The severity of your symptoms is proportional to the amount you eat from the offending food.Even trace amounts of the offending food can produce severe symptoms.

Common offending foods:

  • Lactose intolerance (dairy products).
  • Fructose malabsorption.
  • Alcohol intolerance.
  • FODMAP intolerance (as with People with IBS).

Common offending foods: (examples)

  • Raw meat, seafood.
  • Nuts, peanut
  • Mustard.
  • Rice
  • Some vegetables and fruits.



2. Irritable bowel syndrome.

Many people are another widespread condition that can keep you getting diarrhea (on and off).

Research estimates that up to 40% of IBS sufferers don’t know they have it. This is because the symptoms are usually moderate and non-specific.

Sporadic attacks of diarrhea and abdominal pain that come and go may suggest IBS. The principal feature of IBS is abdominal pain. Having random episodes of diarrhea without abdominal pain precludes IBS.

Irritable bowel syndrome is linked to intolerance to FODMAPs. FODMAPs are a group of short-chain carbohydrates that are difficult to digest.

How to suspect IBS (symptoms):

  • Abdominal pain that is recurrent at least one day per week (for several months).
  • The pain improves or worsens after you poop.
  • The pain is associated with a change in stool form (becoming more loose or hard).
  • The pain is associated with a change in stool frequency (diarrhea or constipation).
  • All the symptoms come and go intermittently in attacks (including on-and-off diarrhea).
  • Triggers are usually food and psychological stress.
  • Random diarrhea with mucus is frequent with IBS.

3. Stress and anxiety-related diarrhea.

You’re not alone if you get diarrhea in stressful or anxiety-producing situations. Psychological stress massively affects your digestion.

You may experience random diarrhea attacks solely due to stress.

Stress and anxiety can affect your digestive system in multiple ways. For example, anxiety is way more common in IBS sufferers than in the general population (reference).

On-and-off diarrhea is often related to worry, anxiety, or stress. Attacks of intermittent diarrhea are symptoms of psychological dysfunction.

If you are unsure about the relation, consult your doctor or gastroenterologist.

RELATED: Anxiety And IBS: In-depth Guide.

4. Medications.

Many drugs can lead to recurrent diarrhea (on and off pattern). Review your list of medication and their relation to diarrheal attacks.

Drugs are often overlooked as a cause of sporadic attacks of diarrhea. Diarrhea is a reported side effect of over 700 medications (reference).

Check your list of medications for any medications that can cause random diarrhea:

  • Metformin:
    A famous anti-diabetic drug used in patients with type 2 diabetes mellitus.
    Metformin-induced diarrhea is widespread, especially if you take high doses.
  • Antibiotics:
    Antibiotics may cause a permanent change in the microbial environment inside your gut. This predisposes to disturbances in your digestion.
    Chronic diarrhea or random attacks of diarrhea, distention, bloating, and even IBS may result from antibiotics.
    The most common antibiotics causing diarrhea include penicillins, cephalosporins, and clindamycin antibiotics. A more detailed list is here.
  • GERD and gastritis medications.
    Proton pump inhibitors include Esomeprazole (Nexium®), Omeprazole (Prilosec®), and others.
    When used for long periods, these medications may disturb the natural microbial environment inside your gut. As a result, random attacks of diarrhea and other digestive symptoms may result.
  • Immuno-suppressive drugs.
    Treatment of immune-mediated disease involves medications that inhibit your immunity. In addition, medicines such as methotrexate (Trexal®), Mycophenolate mofetil (CellCept®), and others may cause diarrhea.
    Consult your doctor about random diarrhea attacks if you have any immune-medicated disease. Examples include Systemic lupus erythematosus, Rheumatoid arthritis, systemic sclerosis, etc.
  • Chemotherapy drugs
    cancer patients who receive chemotherapy may experience severe diarrhea. However, milder forms or random attacks of diarrhea may also occur.
  • Furosemide (Lasix®)
    Furosemide is a diuretic medication that is used for hypertension and heart disease.

5- Exagerated gastro-colic reflex.

When your stomach receives food, it signals your colon to move more (reference).

This happens physiologically & helps the colon emptying to receive the waste from the next meal.

Over-activity of your digestive system is due to abnormal hypersensitivity of its wall or psychological stress (reference).

Abnormally exaggerated gastro-colic reflex can cause many symptoms, such as on and off diarrheal attacks, the urge to poop after meals, and abdominal pain.

Irritable bowel syndrome is thought to occur due to an exaggerated gastro-colic reflex.

Learn more about the gastro-colic reflex.

6- Post-cholecystectomy diarrhea.

Post-cholecystectomy diarrhea is a common condition after gallbladder surgery. Therefore, if the onset of diarrheal attack started after cholecystectomy, think of post-cholecystectomy syndrome.

This condition is common and can affect up to 20% of people after gallbladder removal. Random attacks of diarrhea can happen because your colon cannot handle excess bile acids. (reference)

A characteristic feature of this type of diarrhea is a severe urge to poop. It may become severe when soiling accidents occur (secondary bile acid diarrhea).

The diarrhea attacks are related to the ingestion of fatty foods. Post-cholecystectomy diarrhea can last anytime between a few weeks to several years.

Consult your doctor if you believe that random diarrhea is related to cholecystectomy.

7- Others (less frequent causes of random diarrhea).

A. Colorectal cancer.

Colorectal cancer is not uncommon. Also, intermittent diarrhea can be a sign of colorectal cancer. This is especially important if the onset of diarrhea is at an older age (after age forty-five).

The most common symptom of colon cancer is a prolonged change in bowel habits (random attacks of diarrhea or constipation).

Other symptoms include blood in stool, weight loss, lost appetite, unexplained fever, or anemia.

Prevalence of symptoms in colon cancer patients (reference):

  • Change in bowel habits (You will keep getting unexplained on-and-off diarrhea or constipation): in 75% of patients with colon cancer.
  • Blood in the stool (dark or bright red): 50%.
  • A sense of rectal mass: in 25%.
  • Anemia (iron deficiency): in 10%.
  • Isolated abdominal pain: only 3.8% of cases.
  • Other symptoms such as weight loss, unexplained fever, nausea, and anorexia are also present.

Learn more about colorectal cancer and your gut symptoms.

A- Diabetes Mellitus.

Damage to the nerves supplying your gut can result from long-lasting uncontrolled diabetes. (reference)

This can speed up (or slow down) your gut motility. In addition, changes in bowel habits, such as getting on and off diarrhea or constipation attacks, are common if you have diabetes.

B- Celiac disease.

Celiac disease is the most extreme form of food intolerance. It affects about 1%  of people (reference).

Celiac disease is an intolerance to a protein found in wheat, rye, and barely. The protein is called Gluten.

Eating the offending foods can result in diarrhea (chronic or intermittent attacks of diarrhea). Learn more about celiac disease.

C- Endocrinal diseases.

The below condition is less frequent and has more complex symptoms. Often, they have multi-system symptoms and are not confined to diarrhea. Consult your doctor if you have troublesome diarrhea of unclear cause.

  • Thyrotoxicosis (hyperactive thyroid gland).
  • Carcinoid syndrome.
  • Medullary carcinoma of the thyroid gland.
  • Gastrinoma.
  • Vipoma.
  • Glucaginoma.
  • Somatostatinoma.
  • Systemic mastocytosis.
  • Addison’s disease.

Learn more HERE and HERE.

D- Less common intestinal diseases

  • Inflammatory bowel disease (Crohn’s disease and ulcerative colitis).
  • Tropical sprue.
  • Whipple’s disease.
  • Eosinophilic gastroenteritis.
  • Microscopic colitis.
  • Intestinal lymphoma.
  • Mesenteric ischemia.
  • Radiation to the intestines.
  • Chronic giardiasis.
  • Intestinal lymphangiectasia.

The causes of intermittent diarrhea are numerous and complex. We couldn’t provide the ultimate answer without reviewing your medical history, examinations, and investigations.

Please call your doctor if you keep getting troublesome diarrhea attacks.