A Patient’s Guide to Understanding Diarrhea

Diarrhea is a very common digestive issue characterized by frequent, loose, or watery bowel movements. While it is rarely pleasant to talk about, your bowel habits give us important clues about what is going on inside your body. Below is a basic guide to help you understand what might be causing your symptoms and what to do next.

ACUTE diarrhea (lasting less than 2 weeks)

Acute diarrhea comes on suddenly. Most of the time, this is your body's natural way of flushing out an infection or a toxin you may have accidentally eaten.

If your symptoms include high fever (over 102°F), bloody stools, confusion, or extreme thirst and dark urine…

● This is a medical emergency, please seek medical care immediately. These
are "red flag" warning signs. They can point to a severe bacterial infection (such
as Salmonella or severe E. coli) or intestinal ischemia, a serious condition where
your gut isn't getting enough blood flow. 

If your symptoms are sudden, watery diarrhea combined with heavy nausea and vomiting…

● It is likely food poisoning or a stomach bug. Food poisoning happens when
you eat food contaminated with certain bacteria (like Staphylococcus). A stomach
bug, medically known as viral gastroenteritis, is often caused by the highly
contagious norovirus. These illnesses hit hard and fast, but usually pass once the
bug is flushed from your system.

If your symptoms are watery diarrhea that started after recent travel, camping, or outdoor recreation…

● It is likely traveler's diarrhea or a parasitic infection. Traveling introduces your stomach to new local bacteria that your body isn't used to. Alternatively, if you've been swimming in lakes or drinking untreated water, you may have picked up a microscopic parasite like Giardia.

If your symptoms are frequent, smaller bowel movements that contain mucus or blood…

● It is likely an invasive bacterial infection. Certain bacteria (like Campylobacter,
Salmonella, or Shigella) don't just pass through your system—they actually
invade and irritate the lining of your intestines. This active inflammation is what
causes mucus and blood to appear in the toilet.

CHRONIC diarrhea (lasting more than 4 weeks)

When diarrhea lingers for a month or longer, it usually points to a food sensitivity, a medication side effect, or an underlying medical condition rather than a passing
stomach bug.

If your symptoms are greasy, foul-smelling, or floating stools after eating wheat, barley, or rye…

● It is likely Celiac disease. This is an autoimmune condition where your body
reacts poorly to gluten. Eating gluten physically damages the lining of your small
intestine, making it hard for your body to absorb fats and nutrients. This
unabsorbed fat is what causes the stool to look greasy and float.

If your symptoms are watery stools shortly after consuming milk, ice cream, or soft cheeses…

● It is likely lactose intolerance. This means your digestive system is missing the
enzyme needed to break down milk sugars (lactose). When those intact sugars
travel down into your colon, they draw excess water in with them, resulting in
watery diarrhea.

If your symptoms include stools with blood or mucus, or if the urge to go is
actually waking you up from sleep at night…

● It is likely inflammatory bowel disease (IBD). Waking up at night to use the
bathroom is a strong signal that there is physical inflammation in your digestive
tract. This can be caused by chronic conditions like ulcerative colitis or Crohn’s
disease, which create persistent irritation and ulcers in the bowel.

If your symptoms started shortly after you began taking a new prescription…

● It is likely medication-induced diarrhea. Many medications can speed up your
digestion or disrupt the "good" bacteria in your gut. The most common culprits
include antibiotics, diabetes medications (like metformin or GLP-1 injections),
and certain antidepressants (SSRIs). Never stop a prescribed medication without
talking to your doctor first.

If your symptoms persist, but all your blood work, stool tests, and colonoscopy results come back completely normal…

● It is likely irritable bowel syndrome (IBS). With IBS, the physical structure of
your bowel is perfectly healthy—there are no ulcers or infections. Instead, the
nerves and muscles controlling your digestion are simply overly sensitive and
moving things through your system too quickly.

Next steps: what to do when you have diarrhea?

When to seek medical help:

While most cases of diarrhea will pass on their own, some situations require a doctor's attention.

● Go to the emergency room if you experience any "red flag" warning signs. This
includes a high fever (over 102°F), bloody stools, confusion, or signs of severe
dehydration like extreme thirst and dark urine. These symptoms require
immediate medical care.

● Contact your primary care provider if you experience a significant change in
your bowel habits that lasts more than 2-3 days with no improvement. You
should also call our office if you are unable to keep any liquids down or if you feel
dizzy and weak when standing up.

Managing your symptoms at home:

If your symptoms are mild and you do not have any of the red flag warnings mentioned above, your main goal at home is to stay hydrated and rest your digestive system.

● Treating fluid loss: Diarrhea pulls water and important minerals (electrolytes)
out of your body. It is critical to drink plenty of fluids. Reach for water, clear
broths, or oral rehydration solutions (like Pedialyte or diluted sports drinks). Avoid
sugary sodas, highly caffeinated drinks, and alcohol, as these can actually make
dehydration and diarrhea worse.

● Using over-the-counter (OTC) medicines: Antimotility agents (like Imodium) or
medications containing bismuth (like Pepto-Bismol) can slow down your bowels
and offer relief. Important safety note: Only use these if your diarrhea is watery
and mild. If you have a high fever or bloody stools, do not take these
medications, as your body is actively trying to flush out a harmful infection.

● Choosing the right diet: Stick to bland, easy-to-digest foods while your stomach is recovering. The classic "BRATY" diet is very helpful here: Bananas, Rice,
Applesauce, Toast, and Yogurt. Avoid greasy, spicy, or high-fiber foods, and hold
off on dairy products (like milk and cheese) until your bowel movements return to
normal.

How to prevent diarrhea:

The best way to deal with stomach bugs and infections is to stop them before they start. You can protect your digestive tract by following a few basic hygiene habits:

● Wash your hands: This is your best defense against infection. Always wash
your hands thoroughly with soap and warm water after using the bathroom, after
changing diapers, and before you eat or prepare food.

● Practice good food safety: Keep raw meats separate from your fresh produce.
Ensure all meats are cooked thoroughly, wash your fruits and vegetables before
eating, and promptly refrigerate any leftovers so bacteria do not have time to
grow.

● Be cautious when traveling: If you are visiting an area where the local tap
water might be unsafe, drink only sealed, bottled water. Avoid ice cubes, raw
salads, and unpeeled fruits in these areas.