Acute Diarrhea: Causes, Risks, and What to Do When It Strikes

When acute diarrhea, a sudden, short-term bout of loose or watery stools that typically lasts less than two weeks. Also known as infectious diarrhea, it's one of the most common reasons people end up in urgent care or skip work for a day or two. It’s not just uncomfortable—it can be dangerous, especially for kids, older adults, and people with chronic illnesses. The real risk isn’t the diarrhea itself, but what it drains from your body: fluids and electrolytes. Left unchecked, that leads to dehydration, a dangerous loss of body water and salts that impairs organ function, and that’s when things get serious fast.

Most cases of acute diarrhea come from viruses—norovirus, rotavirus, or even bad sushi from last night. Bacteria like E. coli or Salmonella are next on the list, often tied to undercooked meat or contaminated water. Parasites? Less common, but they show up in travelers or people who drink from mountain streams. What most people don’t realize is that oral rehydration salts, a simple mix of sugar, salt, and water proven to replace lost fluids better than soda or sports drinks are the gold standard for treatment. You don’t need antibiotics. You don’t need fancy pills. You need to replace what you’re losing, and fast. Antidiarrheal meds like loperamide can help you feel better quicker, but they can also trap harmful bugs inside your gut if used too early. And if you’re on medications like antibiotics or diabetes drugs, diarrhea might be a side effect—not an infection at all.

Here’s what you need to watch for: blood in stool, fever over 102°F, dizziness when standing, or not peeing in 8 hours. These aren’t "wait and see" signs—they’re red flags. If you’re over 65, pregnant, or have kidney disease or heart failure, even mild diarrhea needs attention. The good news? Most cases clear up in 2-3 days with rest and fluids. The bad news? Many people reach for Imodium first, then wait too long to drink water. That’s like trying to put out a fire with a spray bottle. You need volume. You need consistency. You need to treat the body’s real need, not just the symptom.

The posts below cover exactly what you need to know when diarrhea hits—when to treat it at home, when to call a doctor, how medications can trigger it, and why some people are more at risk than others. You’ll find real advice on managing side effects from drugs that mess with your gut, how to avoid dehydration when you’re already on meds for other conditions, and what to do if you’re stuck with chronic issues that start with a sudden bout of loose stools. No fluff. No guesswork. Just what works.