Diarrhea lasting a full week falls right at the boundary between acute and persistent. Most acute diarrhea resolves on its own within a few days, so if yours has continued for seven days, it’s time to take active steps: manage dehydration, adjust what you’re eating, and figure out whether you need medical testing. Medically, diarrhea that extends beyond two weeks is classified as “persistent,” and anything past four weeks is considered chronic. A week in, you’re not in crisis territory, but you shouldn’t ignore it either.
Why Diarrhea Lasts This Long
A stomach bug from a virus typically clears in two to three days. When diarrhea stretches to a week, the cause is often something your body can’t flush out as quickly. Bacterial infections from Salmonella or Shigella can drag on longer than viral ones. Parasitic infections, particularly Giardia, are a common culprit behind diarrhea that won’t quit. Giardia spreads through contaminated water (including streams, lakes, and sometimes public pools) and can cause watery diarrhea, cramping, and bloating that persist for weeks if untreated.
Infections aren’t always to blame. Several commonly used medications cause diarrhea as a side effect. Antibiotics are a well-known trigger, sometimes by disrupting normal gut bacteria and occasionally by enabling a secondary infection called C. difficile. Metformin (used for diabetes), ibuprofen and naproxen, magnesium-containing antacids, and proton pump inhibitors for heartburn can all cause or worsen loose stools. If you recently started or changed a medication and then developed diarrhea, that connection is worth raising with your doctor.
Food intolerances can also keep diarrhea going. Lactose (in dairy) and fructose (in sweetened drinks, fruit juice, and packaged desserts) draw extra water into the intestines when they aren’t absorbed well. Sugar alcohols, found in sugar-free gum and candies, do the same thing. If you’ve been eating these foods regularly while sick, they may be prolonging your symptoms even after the original trigger has passed.
Hydration Is the Priority
A week of diarrhea means a week of losing fluids and electrolytes faster than normal. Dehydration is the most immediate risk, and it can sneak up on you. The simplest way to check is your urine color: pale yellow means you’re adequately hydrated, while dark yellow or amber signals you need more fluids. Researchers use an eight-point urine color scale that ranges from 1 (pale yellow) to 8 (dark greenish-brown), and anything above a 4 should prompt you to drink more.
Water alone isn’t enough when you’ve been losing fluids for days. You’re also losing sodium, potassium, and other electrolytes. Oral rehydration solutions (available at any pharmacy) are designed to replace exactly what diarrhea depletes. Broth-based soups and diluted sports drinks can help too, though sports drinks tend to be high in sugar, which can make diarrhea worse in large amounts. Signs that dehydration is becoming serious include excessive thirst, dry mouth, dizziness or lightheadedness, very little urination, and dark-colored urine. Severe weakness or feeling faint means you need medical attention promptly.
What to Eat and What to Avoid
You don’t need to stop eating. In fact, continuing to eat helps your intestinal lining recover. The key is choosing foods that won’t add to the problem. Stick with bland, low-fat, easy-to-digest options: rice, plain toast, bananas, boiled potatoes, and lean chicken or fish. Small, frequent meals are easier on your gut than three large ones.
The list of things to avoid matters more than the list of things to eat. Cut out:
- Dairy products containing lactose, especially milk and ice cream (yogurt is often better tolerated)
- Caffeine from coffee, tea, and cola, which speeds up gut motility
- Alcohol, which irritates the gut lining and worsens dehydration
- High-fat and fried foods, including pizza and fast food
- Sugary drinks and fruit juices high in fructose
- Sugar-free products containing sugar alcohols like sorbitol or xylitol
These aren’t permanent restrictions. Once your stools return to normal, you can gradually reintroduce these foods over a few days.
Over-the-Counter Options
Loperamide (the active ingredient in Imodium) slows down intestinal contractions, giving your body more time to absorb water from stool. For adults, the standard approach is 4 mg initially, then 2 mg after each loose stool, up to a maximum of 8 mg per day when using it without a prescription. It can provide real relief, but there are important exceptions: do not take loperamide if you have bloody or black stools, a high fever, or if your diarrhea started after a course of antibiotics (which raises the possibility of C. difficile infection). In those situations, slowing down the gut can trap the very bacteria or toxins your body is trying to expel.
Bismuth subsalicylate (Pepto-Bismol) is a milder option that can reduce the frequency of loose stools and ease cramping. It’s generally safe for short-term use, though it will turn your tongue and stool black, which is harmless but startling if you aren’t expecting it.
Probiotics have mixed evidence for diarrhea that’s already ongoing. Certain strains, particularly Lactobacillus rhamnosus GG, have been shown to shorten the duration of rotavirus diarrhea in clinical studies. The effect is clearest for viral diarrhea in children. For adults with non-specific or bacterial diarrhea, the benefit is less consistent. Taking a probiotic is unlikely to hurt, but it probably won’t be the thing that resolves a week-long episode on its own.
When a Week Is Too Long to Wait
At the one-week mark, it’s reasonable to call your doctor, even if your symptoms feel manageable. Diarrhea that persists this long sometimes points to an infection that needs targeted treatment rather than just time. Giardia, for instance, won’t clear without prescription medication. C. difficile requires specific antibiotics different from the ones that may have triggered it.
Certain symptoms mean you should seek care sooner rather than later: a fever above 102°F (39°C), blood or black color in your stool, or signs of significant dehydration like dizziness, very dark urine, or severe weakness. These warrant a same-day visit or urgent care, not a wait-and-see approach.
Your doctor will likely start with a stool sample. The two most common tests are a stool culture (which checks for bacterial infections like Salmonella and Shigella) and an ova and parasite exam, which detects Giardia and other parasitic infections. The parasite test sometimes requires two or three separate stool samples collected on different days, because parasites aren’t shed continuously. If you’ve recently taken antibiotics, a specific test for C. difficile toxin is standard. These tests are straightforward, and results typically come back within a few days, pointing toward the right treatment.
Medications That May Be Contributing
If you’re taking a medication known to cause diarrhea, a week of symptoms is a signal to talk to your prescriber. Antibiotics are the most frequent offender, but metformin causes diarrhea in roughly 10-20% of people who take it, particularly in the first weeks of use. NSAIDs like ibuprofen and naproxen can irritate the gut lining enough to cause persistent loose stools. Even magnesium supplements or magnesium-containing antacids act as osmotic laxatives at higher doses. Some herbal teas contain senna, a natural laxative that can cause diarrhea without you realizing the connection.
Don’t stop a prescribed medication on your own, but do let your doctor know what’s happening. In many cases, adjusting the dose, switching to a different formulation, or taking the medication with food can resolve the problem without sacrificing the treatment you need.