Let’s talk about diarrhea. Nobody likes talking about diarrhea. I know, I mostly talk about constipation because I feel like constipation is diarrhea’s more stubborn, less sexy cousin… but everyone experiences diarrhea at some point. It’s more common than constipation, and usually self-limiting, which means temporary.
My family and I just went through a week and a half of some GI bug that’s been floating around (that is why this newsletter is late!), so diarrhea is at the top of my mind. Going thirty times a day definitely counts as diarrhea, but what is the minimum definition?
Understanding what counts as diarrhea, why it happens, and when to worry can help you manage symptoms and know when to seek care.
Let’s start with the basics.
Clinically, diarrhea is defined as:
Three or more loose or watery stools per day, or
Stools that are significantly looser than your normal pattern
Using the Bristol Stool Scale, diarrhea usually corresponds to:
Type 6: Mushy stool with ragged edges
Type 7: Completely liquid stool
Diarrhea occurs when the intestines move contents too quickly or fail to absorb enough water.
Your colon’s normal job is to reclaim water from stool. When that process is disrupted, stool becomes loose.
Diarrhea isn’t one disease—it’s a symptom with many possible triggers.
Infections (Most Common)
Viruses, bacteria, and parasites can irritate the intestines.
Common examples include:
Food poisoning bacteria
Traveler’s diarrhea organisms
Norovirus (see below)
These usually resolve on their own within a few days.
Is There a Diarrhea Virus Going Around in the U.S. Right Now?
Yes — the most common “diarrhea virus” circulating in the United States right now is norovirus, often called the stomach bug or winter vomiting disease.
Norovirus is the leading cause of vomiting and diarrhea in the United States and spreads extremely easily in households, schools, cruise ships, and nursing homes.
Some key things to know:
Symptoms: sudden nausea, vomiting, watery diarrhea, stomach cramps, sometimes fever and body aches
Onset: typically 12–48 hours after exposure
Duration: most people recover within 1–3 days
Spread: extremely contagious through contaminated food, surfaces, or close contact with infected people
Norovirus outbreaks happen year-round but peak between November and April, which is why you hear about them most in winter.
In the U.S., norovirus causes about 19–21 million illnesses each year and thousands of hospitalizations.
The most important prevention strategies for infection associated diarrhea are:
thorough handwashing with soap and water (sing your ABCs!)
cleaning contaminated surfaces
staying home for 48 hours after symptoms stop
Diet and Food Intolerance
Certain foods can trigger diarrhea, including:
Lactose (milk products)
Artificial sweeteners (sorbitol, xylitol)
Excess caffeine or alcohol
Very fatty foods
For some people, FODMAP carbohydrates can also trigger loose stools. This type of diarrhea can also be call gastroenteritis, which is inflammation of the stomach and small bowel, making them unable to absorb fluids.
Medications
Many medications can cause diarrhea (in fact, most medications will include diarrhea or constipation as possible side effects), the most common ones are:
Antibiotics (antibiotic-associated diarrea, AAD, can be helped with probiotics)
Magnesium-containing antacids
Metformin
Some cancer therapies
Antibiotics may also disrupt normal gut bacteria, which worsens and prolongs diarrhea.
Digestive Disorders
Chronic diarrhea can be associated with conditions such as:
Irritable bowel syndrome (IBS-D)
Inflammatory bowel disease
Celiac disease
Bile acid malabsorption
A rare but increasingly common diarrhea diagnosis: microscopic colitis.
These require medical evaluation.
Treatment depends on the underlying cause, but most cases improve with supportive care.
Hydration Is Key!!!
The biggest risk of diarrhea is dehydration.
Focus on:
Water
Oral rehydration solutions
Broths and electrolyte drinks
I generally load up on Liquid IV, Gatorade, coconut water, and chicken broth and keep sipping. Warm fluids feel better, BTW.
Short-term dietary changes may help:
Bananas
Rice
Toast
Applesauce
Avoid heavy, greasy foods until symptoms improve.
Depending on the situation, doctors may recommend:
Loperamide (Imodium) to slow bowel movement
Bismuth (Pepto-Bismol) for mild infectious diarrhea
Antibiotics for certain bacterial infections
These should be used appropriately and not in every case. I rarely take or give any of these to my kids because sometimes the diarrhea has to ‘clear itself out’. Your body is probably getting rid of stuff it doesn’t like. Only when it’s gone on for days do I reach for the Pepto. Not when it first starts.
Most diarrhea resolves within a few days, but seek medical care if you have:
Signs of dehydration
Fever
Blood in stool
Severe abdominal pain
Diarrhea lasting more than 3–5 days
Chronic diarrhea may require further testing.
Diarrhea is common and often temporary, usually caused by infections, diet, medications, or digestive conditions.
The key priorities are:
Hydration
Symptom control
Monitoring for warning signs
And if symptoms persist, your body may be telling you something worth investigating.
Your gut is good at sending signals.
The trick is knowing which ones matter.
References
DuPont HL. Acute infectious diarrhea in adults. New England Journal of Medicine. 2014;370:1532–1540.
Schiller LR, Pardi DS, Spiller R. Gastroenterology review of chronic diarrhea. Gastroenterology. 2017;152:515–532.
Lacy BE et al. Bowel disorders. Gastroenterology. 2016;150:1393–1407.
WHO. Oral rehydration salts: Pro
