What causes spontaneous diarrhea?

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Last updated: July 7, 2025View editorial policy

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From the Guidelines

Spontaneous diarrhea is typically caused by viral infections, bacterial infections, parasitic infections, food intolerances, certain medications, inflammatory bowel diseases, irritable bowel syndrome, or food poisoning, with the most recent evidence suggesting that norovirus and Salmonella enterica subspecies are leading pathogens 1. The causes of spontaneous diarrhea can be diverse, including:

  • Viral infections (like norovirus or rotavirus)
  • Bacterial infections (such as E. coli, Salmonella, or Campylobacter)
  • Parasitic infections
  • Food intolerances (particularly lactose intolerance)
  • Certain medications (including antibiotics, antacids containing magnesium, and some cancer treatments)
  • Inflammatory bowel diseases (Crohn's disease or ulcerative colitis)
  • Irritable bowel syndrome
  • Food poisoning According to the 2017 Infectious Diseases Society of America clinical practice guidelines for the diagnosis and management of infectious diarrhea, the burden of acute gastroenteritis has been reduced since the implementation of rotavirus vaccines, but norovirus and Salmonella enterica subspecies remain leading causes of illness, hospitalization, and death 1. It's also important to note that altered bile acid metabolism is a common but frequently undiagnosed cause of chronic diarrhea, affecting about 5% of the population overall 1. In terms of management, treatment depends on the cause, but often includes staying hydrated with water, clear broths, or oral rehydration solutions like Pedialyte, and for mild cases, over-the-counter medications such as loperamide (Imodium) or Bismuth subsalicylate (Pepto-Bismol) can help reduce symptoms 1. If diarrhea persists beyond 2-3 days, is accompanied by severe pain, high fever, bloody stools, or signs of dehydration, medical attention should be sought immediately 1.

From the Research

Causes of Spontaneous Diarrhea

  • Spontaneous diarrhea can be caused by a variety of factors, including gastrointestinal diseases 2, infections 3, 4, and non-gastrointestinal infections 5.
  • Gastrointestinal diseases that can cause chronic diarrhea include irritable bowel syndrome (IBS), inflammatory bowel disease, and other conditions 2.
  • Infectious causes of diarrhea can be bacterial, viral, or parasitic, and can include organisms such as Salmonella, Shigella, Campylobacter, and rotaviruses 3, 4, 6.
  • Non-gastrointestinal infections that can cause diarrhea include malaria, dengue fever, SARS, and community-acquired pneumonia 5.
  • Other factors that can contribute to spontaneous diarrhea include food distribution networks, antibiotic resistance, and postinfectious syndromes 4.

Types of Diarrhea

  • Acute diarrhea is a common illness that can be caused by a variety of microbes, including viruses, bacteria, and parasites 6.
  • Chronic diarrhea can be caused by gastrointestinal diseases, infections, and other factors, and can be a challenging condition to diagnose and treat 2, 3.
  • Infectious diarrhea can be caused by a range of organisms, including bacteria, viruses, and parasites, and can be a significant public health concern 3, 4.

Diagnosis and Treatment

  • The diagnosis of spontaneous diarrhea can be challenging, and may involve a range of tests, including stool tests and endoscopy 2, 3.
  • Treatment of diarrhea depends on the underlying cause, and can include oral or intravenous rehydration, antibiotics, and other medications 2, 6.
  • In some cases, spontaneous diarrhea can be a symptom of an underlying condition that requires medical attention, such as inflammatory bowel disease or irritable bowel syndrome 2.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

[Chronic, non-infectious diarrhea: diagnostics and therapy].

Deutsche medizinische Wochenschrift (1946), 2016

Research

Infectious causes of chronic diarrhoea.

Best practice & research. Clinical gastroenterology, 2012

Research

Infectious diarrhea.

Disease-a-month : DM, 1999

Research

Diarrhea caused by primarily non-gastrointestinal infections.

Nature clinical practice. Gastroenterology & hepatology, 2005

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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