🤮💧 Acute Gastroenteritis in Children (Stomach Bug): Home Care + Red Flags

✅ Most “stomach bugs” are caused by viruses and improve in a few days.
Your main job is hydration, watching for dehydration, and knowing when to seek help.

1) 🧾 Quick “At-a-glance” box (top of page)

✅ Condition name: Acute Gastroenteritis
Common names: Stomach bug, viral gastro, vomiting/diarrhea illness, “food poisoning” (sometimes)

Plain-language summary (2–3 lines):
Acute gastroenteritis is inflammation of the stomach and intestines that causes vomiting and/or diarrhea. It is most often viral and spreads easily. Most children recover with supportive care—especially frequent small sips of fluid.

Who it affects (typical ages):
All ages; dehydration risk is higher in infants and toddlers.

✅ What parents should do today:

• Start oral rehydration right away (small sips often).
• Keep your child urinating regularly (best sign of hydration).
• Continue breastfeeding/formula in infants if tolerated.
• Reintroduce food gradually when ready (small bland meals).

⚠️ Red flags that need urgent/ER care:

• Signs of dehydration (no urine 8–12 hours, very sleepy, dizzy, dry mouth)
• Vomiting green (bilious), vomiting blood, or black “coffee-ground” vomit
• Bloody diarrhea or severe belly pain with a hard/swollen abdomen
• Persistent vomiting unable to keep fluids down
• Severe weakness, confusion, or fast breathing
• Fever in a baby under 3 months

🟡 When to see the family doctor/clinic:

• Symptoms lasting > 1 week
• Frequent recurring episodes
• Weight loss, poor growth, ongoing abdominal pain
• Diarrhea > 7–10 days, or blood/mucus in stool
• Recent antibiotic use (possible C. difficile)

2) 🧠 What it is (plain language)

Acute gastroenteritis is when the gut lining gets irritated, leading to:

• vomiting (stomach tries to empty),
• diarrhea (intestines push fluid out quickly),
• belly cramps, and sometimes fever.

What part of the body is involved? (small diagram required)

Myths vs facts

• Myth: “Diarrhea must be stopped immediately.”
  Fact: The body is clearing the infection. Focus on hydration.
• Myth: “Kids should not eat at all.”
  Fact: Fluids first; once vomiting improves, small foods help recovery.
• Myth: “Only spoiled food causes this.”
  Fact: Viruses are the most common cause, especially in children.

3) 🧩 Why it happens (causes & triggers)

Common causes

• Viruses: norovirus, rotavirus, adenovirus (common in daycare/schools)
• Bacteria: sometimes from undercooked food, contaminated water, travel
• Parasites: less common; consider with prolonged diarrhea or travel

Less common but important causes (brief)

• Appendicitis (vomiting + worsening localized pain)
• UTI (especially in young children with fever/vomiting)
• Intussusception (episodic severe pain, lethargy, sometimes bloody stool)
• Diabetic ketoacidosis (teens: vomiting + dehydration + heavy breathing)

Triggers that worsen symptoms

• Large amounts of juice/sugary drinks (can worsen diarrhea)
• Greasy foods early
• Dehydration (makes nausea worse)

Risk factors

• Young age (higher dehydration risk)
• Daycare exposure
• Recent travel
• Household contact with vomiting illness

4) 👀 What parents might notice (symptoms)

Typical symptoms (most common first)

• Vomiting (often first 24 hours)
• Diarrhea (watery stools)
• Belly cramps
• Mild fever
• Reduced appetite, fatigue

Symptoms by age group

• Infants: poor feeding, fewer wet diapers, sleepier than usual
• Toddlers: vomiting, diarrhea, refusing fluids, cranky
• School-age: abdominal cramps, diarrhea, can often describe dizziness
• Teens: watch for severe dehydration and other diagnoses (migraine, DKA)

What’s normal vs what’s not normal

✅ Often normal: mild fever, watery diarrhea, improving daily, drinking some fluids
⚠️ Not normal: blood in stool, green vomiting, severe persistent pain, dehydration signs, very sleepy/hard to wake

Symptom tracker

• Number of vomits and stools/day
• Stool appearance (blood? mucus?)
• Fluid intake amount
• Urination frequency
• Fever (temperature)
• Energy level

5) 🏠 Home care and what helps (step-by-step)

✅ What to do in the first 24–48 hours (most important section)

Step 1: Hydration plan (tiny sips often)

✅ Do this now:

• Use oral rehydration solution (ORS) if available.
• Give 5–10 mL (1–2 teaspoons) every 2–3 minutes for young kids.
• For older kids: small sips every few minutes.
• If vomiting happens, wait 5–10 minutes, then restart with smaller sips.

Best sign you’re winning: your child is peeing regularly.

Step 2: Feeding plan

• Breastfed infants: continue breastfeeding (short frequent feeds)
• Formula-fed infants: continue formula in smaller amounts if tolerated
• Older kids: once vomiting slows, offer small bland foods:
  • toast, crackers, rice, banana, soup, yogurt if tolerated

Step 3: What drinks to avoid early

• Juice, pop, sports drinks (too much sugar can worsen diarrhea)
• Very concentrated homemade drinks (incorrect salt/sugar ratio)

Step 4: Comfort measures

• Rest, cool room, quiet environment
• Clean skin barrier for diaper rash (zinc oxide)

What usually makes it worse

• Big drinks all at once
• Greasy foods early
• Trying to “force” food when nauseated

6) ⛔ What NOT to do (common mistakes)

Unsafe treatments parents commonly try

• Anti-diarrhea medications without clinician advice (especially in young kids)
• Antibiotics “just in case” (not usually needed and sometimes harmful)
• Home-made salt solutions without reliable recipe (risk of electrolyte imbalance)

“Avoid unless your clinician told you”

• Bismuth subsalicylate in children without guidance
• Multiple supplements/herbals for diarrhea

OTC medication cautions

• Fever/pain: use age-appropriate dosing only (ask clinician if unsure)
• Avoid ibuprofen if dehydrated or vomiting a lot (can irritate stomach and kidneys)

7) 🚦 When to worry: triage guidance

🔴 Call 911 / Emergency now

• Severe trouble breathing, turning blue, fainting
• Signs of shock: very weak, cold clammy skin, very hard to wake

Example: “My child is barely responsive and breathing fast.”

🟠 Same-day urgent visit

• Dehydration: no urine 8–12 hours, very dry mouth, sunken eyes, dizzy
• Persistent vomiting and cannot keep any fluids down
• Green vomit, blood in vomit, black vomit
• Bloody diarrhea or severe belly pain with hard belly
• Fever in baby <3 months

Example: “Vomiting every time they sip and no pee since morning.”

🟡 Book a routine appointment

• Diarrhea lasting > 7–10 days
• Recurrent episodes or weight loss
• Blood/mucus persists in stool
• Recent antibiotics (evaluate for C. difficile)
• Concern for food intolerance or chronic GI disorder

Example: “Diarrhea keeps coming back every month.”

🟢 Watch at home

• Child is drinking some fluids, peeing, and improving day by day
• No red flags

8) 🩺 How doctors diagnose it (what to expect)

What the clinician will ask

• Duration and pattern of vomiting/diarrhea
• Exposure history (daycare, travel, sick contacts)
• Hydration status (urine output)
• Blood/mucus in stool
• Medications (especially antibiotics)

Physical exam basics

• Hydration check (mouth, tears, eyes, heart rate)
• Abdominal exam

Possible tests (and why)

• Stool tests if: blood, severe illness, prolonged diarrhea, travel, outbreaks
• Blood tests if: dehydration/severe illness
• Urine test if fever/vomiting and UTI concern

What tests are usually not needed

• Viral gastroenteritis usually diagnosed clinically—no tests needed if mild and improving

What results might mean

• Viral: supportive care
• Bacterial: may require targeted treatment in select cases
• Dehydration: fluids and monitoring

9) 🧰 Treatment options

First-line treatment

• ORS hydration strategy
• Continue breastfeeding/formula
• Gradual return to food
• Barrier cream for diaper rash

If not improving (next steps)

• Medical review for dehydration, persistent vomiting, blood in stool
• Consider antiemetic (example: ondansetron) clinician-directed if vomiting prevents hydration
• Stool testing if severe/prolonged or blood present

Severe cases (hospital care)

• IV fluids
• Electrolyte monitoring
• Evaluation for obstruction/appendicitis/intussusception if suspected

Medication/treatment details (key ones)

Oral rehydration solution

• What it does: replaces water + salts
• How to give: tiny sips frequently
• Side effects: none if used correctly

Ondansetron (clinician-directed)

• What it does: reduces vomiting to allow hydration
• How to give: as prescribed
• Common side effects: constipation, headache
• Serious side effects (rare): rhythm issues in specific risk situations
• When to stop/seek help: fainting, severe dizziness, allergic reaction
• Interactions: discuss heart conditions or QT-prolonging medicines

10) ⏳ Expected course & prognosis

• Vomiting often improves in 24–48 hours
• Diarrhea may last 3–7 days (sometimes a bit longer)
• “Getting better” looks like:
  • more urination
  • improved energy
  • fewer vomits
  • diarrhea becoming less frequent
• “Getting worse” looks like:
  • fewer wet diapers/urine
  • persistent vomiting
  • new blood in stool
  • increasing abdominal pain

Return to school/daycare/sports

• Return when:
  • vomiting has stopped,
  • fever-free,
  • drinking well and peeing,
  • energy improved.
• Follow local daycare/school illness policies.

11) ⚠️ Complications (brief but clear)

Common complications

• Dehydration
• Temporary lactose intolerance after infection (loose stools with dairy for a short time)
• Diaper rash

Rare serious complications

• Severe dehydration/electrolyte imbalance
• Bacterial complications (rare)
• Misdiagnosis of appendicitis/obstruction (watch red flags)

12) 🛡️ Prevention and reducing future episodes

• Handwashing (best prevention)
• Disinfect surfaces during outbreaks
• Avoid sharing cups/utensils
• Safe food handling (cook meats properly)
• Vaccines: rotavirus vaccine helps prevent severe infant gastroenteritis where part of routine schedule

13) 🌟 Special situations

Infants

• Lower threshold for dehydration and evaluation
• Fever under 3 months needs prompt medical assessment

Teens

• Consider other diagnoses if severe vomiting/dehydration (migraine, DKA)

Kids with chronic conditions (asthma, diabetes, immunosuppression)

• Lower threshold for medical review
• Diabetes: check for ketones if vomiting and dehydration

Neurodevelopmental differences/autism

• Use preferred cups/straws, visual schedules for sipping
• Monitor dehydration closely

Travel considerations

• Carry ORS packets
• Avoid unsafe water/ice in high-risk areas

School/daycare notes

• Encourage hydration access and bathroom breaks
• Strict hand hygiene after diarrhea

14) 📅 Follow-up plan

• Follow up if:
  • symptoms persist > 7–10 days
  • diarrhea is bloody
  • weight loss or poor growth
  • recurrent episodes
• Bring:
  • stool/vomit diary, photos if blood present
  • urine count
  • medication list

15) ❓ Parent FAQs

“Is it contagious?”

Often yes—viral gastroenteritis spreads easily. Keep good hand hygiene and avoid sharing utensils.

“Can my child eat ___?”

Once vomiting improves, small bland foods are fine. Avoid greasy foods early. If diarrhea worsens with dairy, consider a short break and reintroduce slowly.

“Can they bathe/swim/exercise?”

Baths are fine. Avoid swimming until diarrhea has stopped (to prevent spreading germs).

“Will they outgrow it?”

Yes—most viral gastroenteritis resolves fully. Recurrent episodes may need evaluation.

“When can we stop treatment?”

When your child is drinking normally, peeing normally, and symptoms have resolved.

16) 🧾 Printable tools (high-value add-ons)

🧾 Printable: One-Page Action Plan (Stomach Bug)

Hydration plan:

• ORS preferred
• 5–10 mL every 2–3 minutes (young kids)
• Small frequent sips (older kids)
• If vomit → wait 5–10 min → restart smaller

Food plan:

• Continue breastfeeding/formula if tolerated
• Small bland foods when ready
• Avoid juice/pop early

Urgent care if:

• no urine 8–12 hours
• cannot keep fluids down
• green/bloody/black vomit
• bloody diarrhea
• severe/worsening abdominal pain or hard belly
• baby <3 months with fever

🧾 Printable: Medication Schedule Box

(Use only if prescribed.)

• Morning: __________________ Time: ______
• Afternoon: ________________ Time: ______
• Evening: __________________ Time: ______
• Notes / side effects: __________________________

🧾 Printable: Symptom Diary / Tracker

Date: ______

• Vomits today: ____ Diarrhea stools: ____
• Stool appearance (blood/mucus?): _____________
• Fluids taken: _______________________________
• Wet diapers/urine count: _____________________
• Fever: ______ Energy level: _________________
• What helped: ________________________________

🧾 Printable: “Red Flags” Fridge Sheet

⚠️ Urgent/ER: dehydration (no urine 8–12 hours), persistent vomiting, green/bloody/black vomit, bloody diarrhea, severe belly pain/hard belly, very sleepy/hard to wake, baby <3 months with fever.

🧾 Printable: School/Daycare Instructions Page

• Encourage hydration
• Allow frequent bathroom breaks
• Return when vomiting stopped and child can manage normal hydration
• Hand hygiene after toileting

17) 📚 Credible sources + last updated date

Trusted references (examples):

• Children’s hospital guidance on vomiting/diarrhea and dehydration
• National pediatric society parent resources on gastroenteritis and ORS
• Public health resources on infection prevention and hand hygiene

Last reviewed/updated on: 2025-12-30
Local guidance may differ based on your region and your child’s health history.

🧡 Safety disclaimer

This guide supports—not replaces—medical care. If you are worried about your child, trust your instincts and seek urgent medical assessment.

This guide was fully developed & reviewed by Dr. Mohammad Hussein, MD, FRCPC ROYAL COLLEGE–CERTIFIED PEDIATRICIAN & PEDIATRIC GASTROENTEROLOGIST Board-certified pediatrician and pediatric gastroenterologist (Royal College of Physicians and Surgeons of Canada) with expertise in inflammatory bowel disease, eosinophilic gastrointestinal disorders, motility and functional testing, and complex nutrition across diverse international practice settings.

To book an online assessment Email Dr. Hussein’s Assistant Elizabeth Gray at: Elizabeth.Gray@pedsgimind.ca
In the email subject, please write: New Assessment Appointment with Dr. Hussein

Important: This appointment is completely online as Dr. Hussein is currently working overseas. This service is not covered by OHIP