Diarrhea: what to do now, and when to get help

Diarrhea is miserable, but most of the time it’s short-lived. This guide covers what to do in the first few days, what can cause it, how to spot dehydration, and the signs that mean you shouldn’t wait it out.

What counts as diarrhea?

NIDDK defines diarrhea as loose, watery stools three or more times a day, or more often than is normal for you. Other common symptoms include an urgent need to go, tummy cramps, and sometimes losing control of your bowels.

On the Bristol stool chart, diarrhea usually shows up as type 6 (mushy, ragged edges) or type 7 (entirely liquid).

What should I do right now?

From the NHS:

Do	Don’t
Drink lots of fluids, like water or squash, in small sips if you feel sick	Have fruit juice or fizzy drinks, which can make it worse
Rest at home	Give children under 12 medicine to stop diarrhea
Eat when you feel able to; avoiding fatty or spicy food may help	Give aspirin to children under 16
Wash your hands often with soap and water	Prepare food for other people, if you can avoid it
Take paracetamol if you’re uncomfortable, checking the leaflet	Share towels or cutlery

The NHS says to stay off work or school until 2 days after your last bout, and to avoid swimming pools for 48 hours after symptoms stop.

How long does diarrhea last?

Who	Usual course	Get advice if
Adults (NHS)	Usually stops within 5 to 7 days	It lasts more than 7 days: call NHS 111
Adults (NIDDK)	Not specified	It lasts more than 2 days, or 6 or more loose stools a day: talk to a doctor right away
Children (NIDDK)	Not specified	It lasts more than a day: talk to a doctor right away

The two services set slightly different thresholds. If you’re unsure, the safer choice is to ask.

How do I spot dehydration?

Dehydration is the main risk with diarrhea. NIDDK lists:

• extreme thirst or a dry mouth
• peeing less than usual
• feeling tired, dizzy or lightheaded
• skin that doesn’t flatten back right away when pinched

The NHS adds dark, smelly pee. A pharmacist can suggest oral rehydration sachets. If signs of dehydration continue after using them, call NHS 111. Babies and young children can become dehydrated quickly, so get advice early.

What causes diarrhea?

NIDDK splits causes into short-term (acute) and longer-lasting ones:

Short-term causes	Longer-lasting causes
Viral gastroenteritis (a stomach bug)	Food intolerances, like lactose, fructose or sucrose
Food poisoning	Food allergies, such as cow’s milk, soy or eggs
Travelers’ diarrhea	IBS and functional diarrhea
Medicines, like antibiotics or magnesium antacids	Some digestive conditions and past abdominal surgery
Sugar alcohols such as sorbitol in sugar-free sweets and gum	Long-term use of some medicines

If diarrhea keeps coming back after certain meals, our food intolerance guide and diarrhea after eating post can help you work out what to log.

What does a useful log look like?

During a short bug, focus on fluids, not food diaries. For diarrhea that keeps coming back, a log helps:

Mon 12:30  Meal: latte, cheese toastie  tags: dairy
Mon 15:10  Poop: Type 6
Tue 12:45  Meal: soup, bread
Wed 08:00  Poop: Type 4
Thu 12:30  Meal: milkshake  tags: dairy
Thu 14:40  Poop: Type 7
Paper note: no blood, no fever

Loose poop twice, both a few hours after dairy. That’s worth taking to a GP. It’s a lead, not a diagnosis.

Myths vs facts

Myth	Fact
Stop eating until it passes	The NHS says eat when you feel able to.
Fruit juice and fizzy drinks help you rehydrate	The NHS says they can make diarrhea worse.
Anti-diarrhea medicine is fine for everyone	Loperamide isn’t suitable for children under 12 (NHS).
You can go back to work once you feel better	The NHS says wait until 2 days after your last bout.

When should I get help?

What you notice	What to do
Bloody diarrhea or bleeding from your bottom	Call NHS 111 now (NHS)
Diarrhea for more than 7 days, or vomiting for more than 2 days	Call NHS 111 now (NHS)
Signs of dehydration after using rehydration sachets, or you can’t keep fluids down	Call NHS 111 now (NHS)
Worried about a baby under 12 months	Call NHS 111 now (NHS)
Black, tarry stools, or stools with red blood or pus	Talk with a doctor right away (NIDDK)
Severe pain in your abdomen or rectum, or a change in mental state	Talk with a doctor right away (NIDDK)
Vomiting blood, sudden severe tummy ache, severe difficulty breathing, or confusion	Call 999 or go to A&E (NHS)

NIDDK also says people who are pregnant, over 65, taking antibiotics, or have a weakened immune system should keep in touch with their doctor during diarrhea.

Diarrhea: the first few days

• Sip fluids often
• Skip fruit juice and fizzy drinks
• Eat plain food when you feel able to
• Wash your hands and don't prepare food for others
• Stay off work or school until 2 days after it stops
• Get help for blood, dehydration, or diarrhea lasting more than 7 days

Where does PoopAI fit?

For diarrhea that keeps coming back, PoopAI logs each poop as Bristol type 1 to 7 with an optional photo, and meals by photo or text with trigger tags. Weekly reports show whether type 6 and 7 days follow certain foods. It doesn’t track fluids or symptoms like cramps, so keep those on paper.

The bottom line

Most diarrhea is a stomach bug that passes within a week. Focus on fluids, rest, and good hand washing. Get help quickly for blood, dehydration, or diarrhea that won’t settle. If it keeps coming back, start logging. Next: what to eat after a stomach bug.

Editorial note: Written by The FixMyGut team using the NHS and NIDDK sources listed below. It’s general information, not a diagnosis. Facts checked against those sources on November 5, 2026.