Diarrhea: Causes, Treatment & When to See a GI Doctor

Nobody wants to talk about diarrhea. But if you’ve been dealing with it for more than a couple of days, or if it keeps coming back, your body is trying to tell you something worth listening to.

Diarrhea is one of the most common reasons patients come to see us at Colon & Digestive Health Specialists in Conyers, GA. Sometimes it’s straightforward — a stomach bug, a questionable meal, a course of antibiotics. But when it’s frequent, persistent, or comes with other symptoms like blood in your stool or unexpected weight loss, it points to something that needs a proper diagnosis, not just a wait-and-see approach.

This guide covers everything you need to know: what’s actually causing your symptoms, when it’s safe to manage at home versus when you need a specialist, what the diagnostic process looks like, and how we treat diarrhea based on its underlying cause.

Understanding Diarrhea: What It Means

What Is Diarrhea? Understanding the Basics

Diarrhea means passing loose, watery stools three or more times in a single day. Most people have experienced it at some point — it’s one of the most common digestive complaints in the United States, responsible for millions of doctor visits and missed workdays every year.

What matters clinically is how long it lasts and what’s accompanying it. A single day of loose stools after a questionable meal is very different from six weeks of unpredictable urgency that’s disrupting your daily life.

Doctors typically classify diarrhea into two main categories based on duration:

Acute diarrhea lasts less than two weeks. It starts suddenly and usually has a clear trigger — an infection, a medication, or something you ate. Most acute cases resolve on their own with proper hydration.
Chronic diarrhea persists for four weeks or longer, or recurs frequently over time. This category almost always requires medical evaluation because it typically signals an underlying digestive condition rather than a passing illness.

Acute vs. Chronic Diarrhea: Key Differences

Understanding which type you’re dealing with changes everything about how it should be managed.

Acute Diarrhea — What’s Usually Behind It

Acute diarrhea comes on quickly and is most commonly infectious in origin. Your immune system is fighting something, and diarrhea is part of that process.

Common causes:

Viral gastroenteritis — norovirus and rotavirus are the most frequent culprits, particularly in winter months and in community settings like schools and care facilities
Bacterial infections — Salmonella, Campylobacter, E. coli O157:H7, and Shigella are the most commonly identified bacterial causes, often linked to undercooked meat, contaminated produce, or unsafe water
Traveler’s diarrhea — affects up to 40% of international travelers, particularly those visiting regions with different water and food safety standards; caused by E. coli (most commonly), Campylobacter, Salmonella, or parasites
C. difficile (C. diff) — a particularly important cause of acute diarrhea after antibiotic use; antibiotics disrupt normal gut bacteria and allow C. diff to overgrow, sometimes causing severe colitis
Food poisoning — Staphylococcus aureus

Chronic Diarrhea — When It Points to Something More

Chronic diarrhea is a different animal. It rarely resolves without identifying and treating the underlying cause — which is why “just drink fluids and wait” doesn’t work as a long-term strategy.

Common causes:

Irritable Bowel Syndrome (IBS-D) — IBS with predominant diarrhea is one of the most common causes of chronic loose stools in adults under 50. The colon is structurally normal, but gut motility is dysregulated, often triggered by stress, certain foods, and hormonal fluctuations. Diagnosed by symptom criteria (Rome IV), not by testing abnormalities.
Inflammatory Bowel Disease (IBD) — Crohn’s disease and ulcerative colitis cause chronic inflammation in the digestive tract that produces persistent diarrhea, often with blood and mucus, cramping, and fatigue. Unlike IBS, IBD causes visible structural damage visible on colonoscopy and biopsy.
Celiac disease — an autoimmune reaction to gluten that damages the lining of the small intestine, impairing nutrient absorption and causing chronic diarrhea, bloating, and fatigue. Often underdiagnosed for years before being identified.
Lactose intolerance — the inability to digest lactose (milk sugar) leads to bloating, cramping, and diarrhea after consuming dairy products. Extremely common — approximately 36% of Americans have some degree of lactose malabsorption.
Microscopic colitis — a condition where the colon appears normal on colonoscopy but shows significant inflammation under the microscope. Particularly common in women over 50 and often triggered by NSAIDs, PPIs, or SSRIs.
Small intestinal bacterial overgrowth (SIBO) — excess bacteria in the small intestine ferment food before it can be properly absorbed, producing gas, bloating, and watery diarrhea.
Bile acid malabsorption — excess bile acids reaching the colon act as an osmotic laxative, causing chronic watery diarrhea. Often mistaken for IBS-D and responds specifically to bile acid sequestrants.
Thyroid disorders — hyperthyroidism speeds up gut motility significantly, often causing frequent loose stools alongside other hyperthyroid symptoms
Pancreatic insufficiency — when the pancreas doesn’t produce enough digestive enzymes, fat is malabsorbed, producing greasy, foul-smelling, difficult-to-flush stools (steatorrhea)

Symptoms of Diarrhea: What Your Body Is Telling You

The loose stools are obvious. But the accompanying symptoms often give your gastroenterologist the most important diagnostic clues.

Common symptoms that accompany diarrhea:

Abdominal cramps or pain — location and timing matter (before vs. after bowel movements, upper vs. lower abdomen)
Urgent need to reach the bathroom — sometimes with little or no warning
Bloating and excess gas
Nausea, sometimes with vomiting
Fatigue and weakness, particularly with chronic diarrhea due to nutrient malabsorption
Fever or chills (more common with infectious causes)
Blood or mucus in the stool — always warrants prompt evaluation
Unexplained weight loss — a red flag that needs immediate investigation

What Causes Diarrhea? A Complete Breakdown

Category	Specific Causes
Infections	Norovirus, rotavirus, Salmonella, E. coli, Campylobacter, Shigella, C. diff, Giardia, Cryptosporidium
Medications	Antibiotics, metformin, magnesium-based antacids, PPIs, SSRIs, chemotherapy, laxative overuse
Digestive disorders	IBS-D, Crohn’s disease, ulcerative colitis, microscopic colitis, SIBO, bile acid malabsorption
Food intolerances	Lactose intolerance, gluten sensitivity, fructose malabsorption, artificial sweeteners (sorbitol, xylitol)
Systemic conditions	Hyperthyroidism, diabetes, pancreatic insufficiency, liver disease
Stress and anxiety	Disrupts the gut-brain axis, accelerates gut motility — a real and clinically recognized cause

Diarrhea in Adults vs. Children: Different Causes, Different Concerns

In Adults

Adults most commonly develop acute diarrhea from infections or medications, and chronic diarrhea from IBS, IBD, food intolerances, or microscopic colitis. The threshold for seeking medical evaluation should be lower in adults over 50, particularly for new-onset diarrhea — it warrants colonoscopy to rule out colorectal cancer if no clear benign cause is identified.

In Children

Children have a lower fluid reserve, which means dehydration sets in faster and more dangerously than in adults. Rotavirus, norovirus, and E. coli are the most frequent infectious culprits in children. Any child with diarrhea showing signs of dehydration — dry mouth, no tears when crying, no urination in 8+ hours — needs prompt medical evaluation

How We Diagnose the Cause

Foods to Eat and Avoid During Diarrhea

The BRAT diet — bananas, rice, applesauce, and toast — has long been recommended for acute diarrhea. While evidence on its superiority is mixed, these foods are easy to digest, low in fiber, and gentle on an irritated GI tract. They’re a reasonable starting point.

More broadly, focus on:

Plain white rice, plain pasta, boiled potatoes
Bananas, applesauce, canned peaches (in juice, not syrup)
Plain crackers, toast
Boiled or baked chicken without skin
Clear broths and soups
Oral rehydration solutions

How We Diagnose the Cause of Your Diarrhea

Diarrhea is a symptom, not a diagnosis. Figuring out what’s behind it is the most important step — because the treatment for IBS looks nothing like the treatment for C. diff, and the treatment for celiac disease is entirely different from the treatment for microscopic colitis.

Step 1: Detailed Medical History

This is more valuable than most patients realize. How long have symptoms been present? Is diarrhea nocturnal (wakes you up at night — a red flag for organic disease rather than IBS)? Is there blood or mucus? Have you recently traveled, taken antibiotics, or started a new medication? Is there a family history of IBD or colorectal cancer? These answers alone often point toward a diagnosis before any test is run.

Step 2: Stool Testing

Stool analysis can identify:

Bacterial pathogens (Salmonella, Campylobacter, Shigella, E. coli, C. diff)
Parasites (Giardia, Cryptosporidium, Entamoeba histolytica)
Fecal calprotectin — a marker of intestinal inflammation that helps differentiate IBD from IBS (elevated in IBD, normal in IBS)
Fecal elastase — tests pancreatic enzyme output to diagnose pancreatic insufficiency
Occult blood — detects hidden bleeding not visible to the naked eye

Step 3: Blood Tests

Blood work evaluates:

Complete blood count (CBC) — anemia from chronic blood loss or nutritional deficiency, elevated white cells suggesting infection or inflammation
Comprehensive metabolic panel — electrolyte imbalances from diarrhea, liver function, kidney function
C-reactive protein (CRP) and ESR — systemic inflammation markers elevated in IBD
Thyroid function (TSH) — to rule out hyperthyroidism

Step 4: Colonoscopy

A colonoscopy is indicated when chronic diarrhea has no identified cause from initial testing, when there’s blood in the stool, when IBD is suspected, or when the patient is over 45 and due for colorectal cancer screening. During colonoscopy, Dr. Shakoor can:

Visualize the entire colon for inflammation, ulceration, or masses
Take biopsies from multiple sites — essential for diagnosing microscopic colitis (which looks normal to the naked eye) and IBD
Identify and remove polyps simultaneously

Step 5: Upper Endoscopy (EGD)

When chronic diarrhea is accompanied by nausea, bloating, early satiety, or upper abdominal pain, an upper endoscopy examines the esophagus, stomach, and upper small intestine. Small intestinal biopsies during EGD are the gold standard for confirming celiac disease.

Treatment Options for Diarrhea Relief

The cause, duration, and intensity of your symptoms will determine how you are treated. Our clinic provides:

IBS with Diarrhea (IBS-D)

IBS-D management is multifaceted because there’s no single cure — it’s about reducing symptom frequency and severity and improving quality of life:

Low FODMAP diet — eliminating fermentable carbohydrates that trigger IBS symptoms; supervised by a GI dietitian for best results
Antidiarrheal medications — loperamide (Imodium) for acute control; not for daily long-term use
Prescription medications — alosetron (for women with severe IBS-D), eluxadoline, or rifaximin (an antibiotic that works locally in the gut without systemic effects)
Gut-directed psychotherapy — cognitive behavioral therapy and gut-directed hypnotherapy have strong evidence for IBS symptom reduction; the gut-brain connection is real
Stress management — regular exercise, adequate sleep, and stress reduction measurably improve IBS-D outcomes

Inflammatory Bowel Disease (IBD)

IBD requires ongoing gastroenterology management and should not be self-managed:

Aminosalicylates (5-ASAs) — first-line for mild to moderate ulcerative colitis
Corticosteroids — for acute flares; not appropriate for long-term maintenance
Immunomodulators — azathioprine, 6-mercaptopurine for maintaining remission
Biologic therapies — TNF inhibitors (infliximab, adalimumab), vedolizumab, ustekinumab for moderate-to-severe IBD or disease unresponsive to conventional therapy
Surgery — in severe or refractory cases, particularly for ulcerative colitis where colectomy can be curative

Celiac Disease

The only effective treatment for celiac disease is a strict, lifelong gluten-free diet. This means eliminating all wheat, barley, and rye — and carefully reading ingredient labels since gluten is hidden in many processed foods. Most patients experience significant symptom improvement within weeks of eliminating gluten, with mucosal healing taking months to years.

Microscopic Colitis

Stopping the offending medication (NSAIDs, PPIs, SSRIs) if one is identified
Budesonide (a locally acting steroid) is the most effective treatment and produces remission in the majority of patients
Cholestyramine for bile acid-related cases

When to See a Gastroenterologist for Diarrhea

If your diarrhea lasts more than two days or you notice the following, seek medical help:

See a Doctor Within 24–48 Hours If:

Diarrhea with a fever above 102°F (38.9°C)
Blood or pus in your stool
Signs of significant dehydration — extreme thirst, dizziness, little or no urination
Diarrhea in an infant under 6 months old, or any young child who appears lethargic

At Colon & Digestive Health Specialists, Dr. Karim Shakoor brings years of experience in managing chronic and severe gastrointestinal conditions. Don’t ignore the signs—get expert care when it matters most.

Why Choose CDH for Diarrhea Management?

Expert Care: Karim Shakoor, M.D expertise in gastroenterology ensures you receive a high level of care tailored to your specific needs.
Holistic Approach: We treat diarrhea not just as a symptom but as a sign of your overall digestive health, offering solutions that address both immediate relief and long-term well-being.
Accredited Facilities: Our clinic and the Eastside Endoscopy Center are accredited by The Joint Commission, reflecting our commitment to excellence in patient care.

Frequently Asked Questions about Digestive Health Care

What stops diarrhea fast??

For acute diarrhea, the most effective immediate steps are hydration with an oral rehydration solution, a bland low-fiber diet, and rest. Loperamide (Imodium) slows gut motility and can provide faster symptomatic relief for adults — but should not be used if you have a fever or blood in your stool, as it can worsen certain bacterial infections. For chronic diarrhea, there’s no quick fix — the underlying cause needs to be identified and treated.

Is diarrhea a sign of something serious?

Occasional acute diarrhea from a stomach bug or dietary indiscretion is not concerning. Diarrhea that persists beyond two weeks, recurs frequently, or comes with blood, weight loss, fever, or nocturnal symptoms is a different matter entirely — those patterns warrant medical evaluation to rule out IBD, celiac disease, infection, or colorectal cancer.

Can stress cause diarrhea?

Yes — and this isn’t just anecdotal. The gut-brain axis is a real bidirectional communication system between your nervous system and your digestive tract. Psychological stress activates the sympathetic nervous system, releases stress hormones like cortisol, and measurably alters gut motility and microbiome composition. This is the physiological basis of IBS-D, where stress is one of the most consistent triggers.

How long does diarrhea last?

Acute diarrhea from a viral infection typically lasts 1–3 days. Bacterial infections may last 3–7 days. Traveler’s diarrhea usually resolves within 3–5 days with or without treatment. If diarrhea persists beyond 2 weeks, it’s no longer considered acute — and if it’s still present at 4 weeks, it’s classified as chronic and requires medical evaluation.

Should I see a gastroenterologist for diarrhea?

Yes, if diarrhea persists for more than a few days, recurs frequently, or affects your quality of life, it’s important to see a specialist like Dr. Karim Shakoor at Colon & Digestive Health Specialists.

For Life-Threatening Emergencies Call 911

Our location

Colon & Digestive Health Specialists 1805 Honey Creek Commons, Ste B, Conyers GA 30013

Colon & Digestive Health Specialists
Dr. Karim Shakoor, M.D. & Team