What Causes Instant Diarrhea after Drinking Water? Gastroenterologist Explains.

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

Water is not a known trigger of diarrhea. However, getting instant diarrhea after drinking water can be a symptom of chronic diarrhea.

Several diseases are associated with diarrhea. Having chronic or recurrent diarrhea after drinking water requires you to consult your doctor to diagnose.

Too many causes and explanations can be linked to diarrhea after drinking water. Today, we will discuss the most probable causes of such conditions.

After drinking water, possible causes of instant diarrhea include irritable bowel syndrome, dumping syndrome, and exaggerated gastrocolic reflex. Also, other chronic diarrhea diseases can lead to diarrhea after drinking water as IBS, celiac disease, …etc.

1. Irritable Bowel Syndrome.

Irritable bowel syndrome (IBS) is one of the most common and underdiagnosed gut diseases worldwide.

IBS patients from 40% of the gastroenterologist clinic visits. Also, 10-20% of adults in Western countries suffer from IBS (reference).

IBS is a benign functional disease. No definite lesions or inflammations can be detected in the digestive system of IBS patients.

IBS comes in periods of flare-ups and remission. Anything you eat or drink during a flare-up can lead to abdominal pain and diarrhea.

We don’t clearly understand the cause of IBS. IBS is linked to intolerance to a certain group of foods called the FODMAPs. Also, Stress and psychological dysfunction play a major role in IBS.

Instant diarrhea after drinking water can be a sign of irritable bowel syndrome. Many people have IBS, and they don’t know they have it.

Symptoms suggestive of IBS:

  • Recurrent abdominal pain: At least a day per week for the past three months.
  • Diarrhea or constipation: the onset of abdominal pain is often associated with diarrhea, constipation, or mixed bowel movements.
  • Diarrhea can occur instantly after eating or drinking anything (including water).
  • Bloating and gas distension.
  • Sometimes, nausea and loss of appetite.

how is ibs diagnosed

Abdominal pain is essential for the diagnosis of IBS. Instant diarrhea after water drinking without abdominal pain is unlikely to be IBS.

Also, IBS is not associated with night diarrhea, weight loss, or fever. Therefore, the presence of such symptoms excludes IBS.

Read more about we diagnose IBS as doctors.

2. Exagerated Gastrocolic reflex.

Getting instant diarrhea every time you drink or eat anything (including water) may reflex an exaggerated gastrocolic reflex.

Certain people may experience exaggeration of the reflex leading to explosive diarrhea after eating.

Exaggerated gastrocolic reflex may be due to:

  • Psychological stress and anxiety.
  • Eating large meals.
  • Eating fatty foods.
  • Drinking a large amount of cold liquid at once.
  • Some theories attribute Irritable bowel syndrome to the exaggerated gastrocolic reflex.
  • No diarrhea in between meals or during fasting.

From our experience, many people experience frequent bowel movements (even after drinking water) after meals.

Most patients match the irritable bowel syndrome criteria, the exaggerated gastrocolic reflex.

But severe attacks of explosive diarrhea are not typical for the exaggerated gastrocolic reflex. Consult your doctor if you frequently experience recurrent instant diarrhea after eating or drinking.

Learn more about gastrocolic reflex.

3. Dumping syndrome.

Dumping syndrome is often a side effect of previous abdominal surgeries such as:

  • Gastric bypass surgery.
  • Different types of bariatric surgery (weight loss surgery).
  • Remove a part of your stomach for any reason (such as tumors or perforated ulcers).
  • Esophageal surgery.

Stomach dumping is a rapid emptying of your stomach (often due to decreased stomach capacity).

The rapid emptying results in rapid movement of stomach content into your intestine producing:

  • Diarrhea after eating or drinking anything, including water.
  • Feeling full after eating very little.
  • Sudden onset of colics after eating or drinking. It only resolves after passing the stool.
  • Flushing, dizziness, and lightheadedness shortly after eating.
  • Fast heartbeats after eating.

The condition rarely occurs in patients without stomach operations. We diagnose dumping syndrome by a specific test called (scintigraphic gastric emptying study). Learn more about gastric emptying studies.

4. Others

The first three causes are the most common and likely cause of instant diarrhea after drinking water.

However, diarrhea after drinking water can reflect a chronic gastrointestinal disease. All causes of chronic diarrhea can lead to diarrhea after drinking water.

The diseases and conditions below are all possible causes of instant diarrhea after drinking water. It would be best if you saw a doctor. No Rome here to explain each cause.

Chronic diarrheal diseases that can lead to instant diarrhea after eating or drinking:

  • Crohn’s disease and ulcerative colitis.
  • Celiac disease.’
  • Intestinal malabsorption.
  • Bile acid diarrhea.
  • Drug-induced diarrhea, such as antibiotics and non-steroidal anti-inflammatory drugs.
  • Acute and chronic gut infections (gut bugs).
  • Diabetes.
  • Stress and anxiety-induced diarrhea.
  • SIBO (small bowel bacteria overgrowth.
  • Chronic pancreatitis and exocrine pancreatic insufficiency.
  • Gut malignancies and lymphoma.
  • Endocrinal diseases such as hyperthyroidism, Addison’s disease, and hypoparathyroidism.
  • Hormone-secreting tumors such as gastrinoma, carcinoid, and VIPoma).

You need to see a doctor if:

  • Prolonged or recurrent instant diarrhea after drinking water.
  • Diarrhea after eating or drinking anything.
  • Bloody diarrhea.
  • Weight loss.
  • Fever.
  • Significant abdominal pain, anorexia, or vomiting.