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Diarrhea in Japan: What to do (and when to call 119)

Last updated: 2026-03-03

TL;DR (30-second decision)

  • Call 119 now if you have bloody/black stools, severe dehydration (fainting/confusion, very little urine), severe abdominal pain, or you feel seriously unwell.
  • If you’re unsure whether it’s an emergency: Call #7119 (if available).
  • Most mild cases improve with fluids + rest.
  • For children: diarrhea can dehydrate kids quickly—use a child-specific guide (Learn more).

Call 119 immediately (red flags)

Call 119 right away if you have any of these:

  • Blood in stool or black, tarry stools
  • Severe dizziness, fainting, confusion, or you feel you might pass out
  • Very little urine, extreme thirst, dry mouth, or you cannot keep fluids down
  • Severe abdominal or rectal pain, or a hard/swollen belly
  • High fever with worsening symptoms
  • You have serious chronic illness, are immunocompromised, or symptoms are rapidly worsening

(This page is general guidance, not medical diagnosis. If you think it’s an emergency, call 119.)

What you can do right now (home care)

1) Hydration is the priority

  • Take small sips frequently (water, oral rehydration solution/ORS).
  • If you also have vomiting, start with tiny sips every few minutes.

2) Food: keep it simple

  • When you can drink нормально, try bland foods (rice porridge, toast, bananas, crackers).
  • Avoid alcohol, greasy foods, and large meals until you recover.

3) Rest

  • Diarrhea is often self-limited. Rest and focus on fluids.

OTC medicines (use carefully)

Oral rehydration solution (ORS) is often the most helpful OTC option.

Anti-diarrheal medicines (e.g., loperamide)
These may help for short-term, mild diarrhea only if there is NO fever and NO blood.
Do not use anti-diarrheals if you have bloody diarrhea or diarrhea with fever—seek medical advice instead.

Pain/fever medicines (quick note)

  • If you feel unwell and need something for discomfort, acetaminophen (paracetamol) is often a safer choice for the stomach.
  • NSAIDs can irritate the stomach and may not be a good idea when you’re dehydrated or have stomach upset—use cautiously.

When you should see a doctor soon (same day / within 48 hours)

Consider medical care if:

  • Diarrhea lasts more than 2 days without improvement
  • You have signs of dehydration (very little urine, dizziness, intense thirst, dry mouth)
  • You have severe abdominal pain or significant weakness
  • You have fever, or symptoms are getting worse
  • You recently took antibiotics, recently traveled, or you have serious chronic disease

Japan-specific: how to visit a clinic/hospital

  • If you also have fever or cold-like symptoms, many clinics may ask you to call ahead and follow instructions (some may ask you to wait outside).
  • Bring a mask—many medical facilities request it.

What to say (simple English)

Calling #7119 (if available)

“I have diarrhea. It started [time] ago.
I went to the bathroom [number] times today.
I have [fever / abdominal pain / vomiting].
I do/do not see blood in the stool.
Do I need an ambulance? Where should I go?”

Calling a clinic

“Hello. I have diarrhea since [time].
I went [number] times today.
I have [fever / abdominal pain / vomiting].
Can I visit today? Do I need an appointment?”

FAQ

Is diarrhea an emergency?

Sometimes. If you have blood/black stools, severe dehydration, fainting/confusion, severe pain, or high fever with worsening symptoms, treat it as urgent and call 119.

What should I drink?

Small sips frequently—water or oral rehydration solution (ORS).

Can I take an anti-diarrheal medicine?

Only for mild diarrhea without fever and without blood. If you have bloody diarrhea or diarrhea with fever, do not use anti-diarrheals—seek medical advice.

Do I need to call ahead in Japan?

Often yes—especially if you also have fever/cold-like symptoms.

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