Gastroenteritis – Causes, symptoms and management

Overview

Gastroenteritis, often referred to as gastro, is a highly infectious disease of the stomach and intestines that causes vomiting and diarrhoea. It’s quite common in Australia, especially during viral seasons and outbreaks in schools, childcare centres, and aged-care facilities. While gastro is usually short-term, it can cause dehydration if not managed well, especially in young children and older adults. Note: The content of this blog is for informational purposes only and does not replace professional medical diagnosis, advice, or treatment.

What causes gastroenteritis?

Infections or non-infectious irritants can cause gastroenteritis, and the way it is transmitted depends on the underlying cause.  

Cause type	Examples	How it spreads
Viral	Norovirus, Rotavirus, Adenovirus	Contaminated food or water, close contact with infected people
Bacterial	Salmonella, Campylobacter, E. coli	Undercooked food, raw eggs, unsafe water
Parasitic	Giardia	Untreated water, person-to-person contact
Non-infectious irritants	Food intolerances, medications	Reaction to specific triggers

How gastro is spread

Gastroenteritis spreads easily, especially in shared spaces and households.

• Touching contaminated surfaces
• Close contact with someone who is sick
• Eating contaminated food
• Drinking unsafe or untreated water
• Poor hand hygiene

Symptoms of gastroenteritis

The symptoms of gastroenteritis can appear suddenly and vary from mild to severe. Common symptoms include:

• Nausea
• Vomiting
• Diarrhoea (watery stools)
• Stomach cramps
• Fever
• Headache
• Loss of appetite
• Dehydration (a more serious symptom)

Symptoms typically persist for 1 to 3 days, depending on the underlying cause, though some infections can last longer. The primary concern during this period is excessive fluid loss.

How long does gastro last?

The duration of gastroenteritis depends on its cause. Viral gastro usually lasts 24-72 hours, while bacterial gastro can last longer, especially if untreated. If symptoms persist for more than a week or worsen, consult a GP.

When gastro isn’t gastro: Similar conditions

Some conditions can cause symptoms similar to gastro but require different treatment.

• Food poisoning
• Food intolerance (e.g., lactose intolerance)
• Irritable bowel syndrome (IBS) flare
• Appendicitis
• Gallbladder issues
• COVID-19 or the flu

If symptoms are severe, persistent, or unusual, medical assessment is important.

When to see a doctor immediately

Consult a doctor urgently if any of the following occur:

• Persistent vomiting for more than 24 hours
• Signs of dehydration (dry mouth, dizziness, dark urine)
• Blood in stool
• Severe abdominal pain
• High fever
• Symptoms lasting longer than 3–5 days
• Gastro symptoms in young children, older adults, or during pregnancy

If you or a child experience any of these symptoms, call 000 immediately or visit your nearest Emergency Department.

Diagnosing gastroenteritis

Most cases of gastroenteritis are diagnosed based on symptoms. If needed, a GP may request:

• A stool sample (to identify bacteria or parasites)
• Blood tests (rare, for severe cases)
• Hydration assessment

Management: What actually helps

The main treatment for gastroenteritis focuses on rest and replacing lost fluids. Main treatments include:

• Rest
• Fluids and electrolytes
• Oral rehydration solutions
• Small, bland meals (BRAT-style foods, Bananas, Rice, Applesauce, and Toast diet)
• Avoid fatty, spicy foods
• Over-the-counter pain and fever relief.

Antibiotics are usually not required and are only prescribed when a bacterial cause is confirmed.

What NOT to do

Some actions can worsen symptoms or delay recovery:

• Don’t take anti-diarrhoea medication without GP advice
• Avoid sugary drinks (they may worsen diarrhoea)
• Avoid alcohol and caffeine
• Don’t prepare food for others if you're still vomiting or have diarrhoea

Home remedies that can help

These simple measures may help relieve symptoms alongside medical advice:

• Ginger tea for nausea
• Oral rehydration solutions
• Clear soups
• Warm compress for stomach cramps
• Probiotics (may shorten recovery time)

Preventing gastroenteritis

Simple hygiene and food safety measures can significantly reduce the risk.

• Wash your hands often with soap and water
• Avoid sharing utensils
• Wash fresh produce thoroughly
• Cook eggs and meat properly
• Stay home if unwell
• Use safe drinking water when travelling
• Clean surfaces after vomiting or diarrhoea episodes

Gastro in kids: What parents should know

Children are more prone to dehydration and can become unwell quickly. Here are a few important points for parents:

• Kids lose fluids faster than adults
• Signs to watch: dry nappies, no tears, sunken eyes, or lethargy
• Oral rehydration solutions are recommended
• Seek medical care if symptoms worsen or fluid intake is poor

Gastro in older adults or people with chronic illness

Older adults and people with chronic health conditions are more vulnerable to dehydration and complications. It’s important to seek medical advice early, especially if symptoms persist or fluid intake is reduced.

How can Hola Health help

Hola Health makes it easy to get support when gastro symptoms strike:

• Online GP consultations available Australia-wide
• Help identify if symptoms are gastro or something more serious
• Prescriptions for nausea medication if suitable
• Advice on hydration and recovery
• Medical certificates for work or school
• Referrals if further investigation is needed

Note: Telehealth is not suitable for all cases. A physical examination by an in-person GP may be required to assess for signs of severe dehydration or to rule out surgical emergencies like appendicitis.

Conclusion

Gastroenteritis is common and often settles within a short time, with most people recovering with rest and plenty of fluids. Understanding symptoms, managing fluids early, and recognising when to seek medical advice can help prevent complications like dehydration. If symptoms are severe, ongoing, or involve a child, elderly person, or someone with a chronic illness, a general practitioner can help, whether in-person or through telehealth.

FAQs

Is gastroenteritis contagious?

Yes, especially viral gastro, which spreads easily through contact.

How do I know if it’s gastro or food poisoning?

Symptoms can be similar, so a GP uses the timing of symptoms and exposure history to help identify the cause.

Can I go to work with gastro?

No, you should stay home until at least 48 hours after symptoms stop.

How long does gastro last?

It usually lasts 1-3 days, depending on the cause.

What should I drink if I have gastro?

Water and oral rehydration solutions are recommended.

Should I give my child anti-diarrhoea medicine?

No, unless prescribed by a doctor.

When do I need antibiotics?

Only if a bacterial infection is confirmed, you may need antibiotics. However, most cases don’t need them.