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Diarrhea, vomiting and dehydration: when to go to the ER

Vomiting and diarrhea usually pass, and the main thing is to replace lost fluids 1. The danger is dehydration, which can become serious, especially in babies, young children and older adults.

Find urgent care near you Or find the nearest ER. Updated November 15, 2026; every fact links to its source below.
Photo of a person sipping water to stay hydrated

Go to the ER or call 911 if

  • Blood in vomit, or vomit that looks like dark coffee grounds 2
  • Black, tarry or bloody stool, or severe pain in the belly or rectum 3
  • Confusion, fainting, seizures, or a change in alertness 4 3
  • A fever over 102°F with signs of dehydration 4
  • A child who can’t be woken or is too weak to stand (call 911), or is hard to wake, confused, or vomiting blood or green fluid 5
  • A child too weak or drowsy to drink after long-lasting vomiting or diarrhea 6

If you’re not sure, go to the ER. Find the nearest ER.

When urgent care can help

Severe dehydration may need IV fluids 1. We didn’t find a neutral source on whether urgent care clinics give them, so call ahead, or go to the ER if dehydration looks severe.

Find urgent care near you, with hours and phone numbers. Not sure what it costs? See ER vs urgent care cost.

Signs of dehydration

  • Adults: extreme thirst or dry mouth, urinating less, dark urine, feeling tired, dizzy or lightheaded 3
  • Babies and young children: no wet diapers for 3 hours or more, no tears, a sunken soft spot, or drowsiness 3
  • Children may cry with few or no tears and be unusually sleepy or fussy 1

Contact a provider soon if

  • You can’t keep fluids down for 12 hours or more, or have vomited for more than a day 2
  • Adults: diarrhea for more than 2 days, a high fever, or six or more loose stools in a day 3
  • Children: diarrhea for more than a day, or any fever in a baby 3
  • A child has had no urine in more than 8 hours, dark urine, a very dry mouth or no tears 5

Replacing fluids

Drink plenty of liquids to replace what you’ve lost 1. Oral rehydration solutions contain the sugar and salts your body needs 7; sports drinks may not replace them as well 1. Talk with a doctor before giving them to a baby, and keep up breast milk or formula 7.

Adult with mild diarrhea? See a provider online

For an adult with diarrhea and none of the warning signs above, an online visit is one way to get advice on fluids and treatment. Children and anyone showing dehydration signs should be seen in person. You’ll leave ER.com when you continue. More on Diarrhea online.

See a provider online

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Common questions

Diarrhea, vomiting and dehydration: when to go to the ER, answered.

General information, not medical advice or a diagnosis.

When should I go to the ER for vomiting or diarrhea?
Go for blood in vomit or stool, black tarry stool, severe belly pain 3 2, confusion or fainting, or a high fever with dehydration 4.
What are signs of dehydration in a child?
No wet diapers for 3 hours or more, no tears, a sunken soft spot, or drowsiness 3. A child too weak or drowsy to drink needs the ER 6.
How long is too long for diarrhea?
See a provider if it lasts more than 2 days in an adult, or more than a day in a child 3.
See a provider online now Only if it’s not an emergency. ER.com may earn a commission through affiliate links, at no added cost to you.

Related conditions

Nausea & vomiting · Stomach flu · Food poisoning · Diarrhea · Traveler’s diarrhea

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Sources

  1. CDC: About norovirus (Apr. 24, 2024)
  2. MedlinePlus: Nausea and vomiting, adults (reviewed July 22, 2025)
  3. NIDDK: Symptoms and causes of diarrhea (reviewed Sept. 2024)
  4. MedlinePlus: Dehydration (reviewed July 1, 2025)
  5. American Academy of Pediatrics, HealthyChildren.org: Vomiting with diarrhea symptom checker
  6. American Academy of Pediatrics, HealthyChildren.org: Urgent care, ER or pediatrician? A parent guide (updated May 14, 2026)
  7. NIDDK: Treatment of diarrhea (reviewed Sept. 2024)

Last updated November 15, 2026. General information from the sources above, not medical advice or a diagnosis, and not a substitute for being seen. If you’re not sure whether something is an emergency, go to the ER or call 911.

This is not for emergencies.

For life-threatening symptoms, severe chest pain, trouble breathing, or immediate danger, call 911 or go to the nearest emergency department.