Evidence-based|Sources: NIH, WHO, AHA, AGS clinical guidelines|Updated 2026

What counts as diarrhea?

In short Loose or watery stools occurring more often than usual (typically ≥3 times/day). Most brief episodes are viral or food-related and improve in a few days. Older adults are at higher risk of dehydration, so early fluid replacement matters.

Watch for: reduced urination, dry mouth, dizziness on standing, or fatigue — signs of dehydration that need attention.

Urgent warning signs

  • Black stools, visible blood, or severe abdominal pain
  • High fever, repeated vomiting, confusion, or fainting
  • Very little urine, fast heartbeat, or severe thirst
  • Recent antibiotic use with worsening diarrhea (possible C. difficile)
  • Diabetes with high sugars and dehydration symptoms

If these occur, seek urgent medical care.

Common causes

Short-term (usually days)

  • Viral gastroenteritis (“stomach flu”)
  • Foodborne illness (toxins/infection)
  • Traveler’s diarrhea
  • Medication side effects (antibiotics, metformin, magnesium antacids, some sweeteners)

Longer or recurring

  • Lactose intolerance or other food intolerances
  • Irritable bowel syndrome (IBS)
  • Bile acid diarrhea after gallbladder issues
  • Inflammatory bowel disease, celiac disease (less common but important)
  • Chronic infection (including C. difficile after antibiotics)

Hydration & ORS

Fluids first

  • Frequent small sips: water, oral rehydration solution (ORS), clear soups
  • ORS replaces both water and salts; plain water alone may not be enough
  • Limit alcohol, very sweet drinks, and high-caffeine beverages
If you have heart or kidney disease, follow your clinician’s fluid plan. Rapid drinking may worsen swelling or breathlessness — use measured, steady intake.

Home care & food choices

What to eat (first 24–48 hours)

  • Simple, low-fat, low-fiber choices: rice, toast, crackers, bananas, applesauce, yogurt/curd, dal/clear soups
  • Small amounts more often; advance diet as symptoms ease
  • If lactose sensitive, choose lactose-free dairy or curd/yogurt instead of milk

What to limit

  • Greasy/fried foods, heavy spices early on
  • Sorbitol/xylitol (sugar-free candies/gums), very sweet juices
  • Raw salads or high-fiber bran during acute phase

Helpful extras

  • Probiotics or live-culture yogurt may help some cases
  • Gentle rest; avoid strenuous activity until fully rehydrated
Improvement is often seen within 1–3 days for simple viral/food causes. Continue ORS and light foods until comfortable.

Medicine cautions

MedicineNotes for older adultsDiscuss with your clinician
Loperamide (anti-diarrheal) Can slow gut; avoid if high fever or blood in stool Safe short use for non-bloody diarrhea if advised
Bismuth subsalicylate May darken stools/tongue; interacts with blood thinners Check interactions and kidney function
Antibiotics Not routinely needed; some cause diarrhea or C. difficile Use only when indicated (travelers’ with fever, confirmed bacterial)
Metformin, magnesium antacids, orlistat Can worsen diarrhea Ask about dose timing, alternatives, or temporary adjustments
Diuretics (water pills), ACE inhibitors Higher dehydration/low blood pressure risk Sick-day rules; monitor BP/weight and symptoms

Never start/stop medicines without guidance — plans are individualized.

When tests are needed

Consider stool/blood tests if

  • Fever, blood/mucus in stool, severe pain, or illness > 3–7 days
  • Recent antibiotic use, recent hospitalization, or travel
  • Significant dehydration, frailty, or multiple conditions

What may be ordered

  • Stool culture or PCR panel; test for C. difficile when appropriate
  • Electrolytes, kidney function; sometimes thyroid, celiac panel for chronic cases

Prevention & travel tips

  • Handwashing before meals and after bathroom use
  • Cook meats thoroughly; keep hot foods hot and cold foods cold
  • Use safe water; peel fruits/vegetables or wash well

Travel

  • Bottled/boiled water; avoid ice if unsure
  • Carry ORS packets and quick guidance from your clinician

When to contact your clinician

  • No improvement after 48–72 hours, or symptoms for > 1 week
  • Any red-flag sign (blood in stool, high fever, severe pain, confusion)
  • Ongoing diarrhea with weight loss or at night
  • You have heart/kidney disease, diabetes, or are on diuretics and feel dehydrated

Quick answers

Is the BRAT diet required?

No. Simple, low-fat, low-fiber foods are fine. Include protein (dal, yogurt, eggs) and advance as tolerated.

Should I stop dairy?

Some people are lactose sensitive during/after illness. Try yogurt/curd or lactose-free milk first.

When can I use loperamide?

Short-term non-bloody diarrhea without high fever, if your clinician has said it’s okay. Avoid in bloody stools/fever.

How much should I drink?

Frequent small sips aiming for pale yellow urine. If you have heart/kidney issues, follow your fluid plan and call if unsure.

Medical DisclaimerThis article is for educational purposes only and is not a substitute for professional medical advice. Always consult your doctor before starting supplements or changing medications. Learn about our editorial process.
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