Gastrointestinal Infection
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Gastrointestinal infection, or gastroenteritis, inflames the stomach and intestines, causing diarrhea, vomiting, and cramps, and is usually caused by bacteria, viruses, or parasites.
Key facts
- Gastrointestinal infection, often called gastroenteritis or "stomach flu," inflames the stomach and intestines and is caused by bacteria, viruses, or parasites.
- It produces diarrhea, nausea, vomiting, and abdominal cramps, and typically clears within a few days.
- Most cases resolve with fluids and rest; confirmed bacterial infection may need an antibiotic such as ciprofloxacin.
- Oral rehydration salts are the cornerstone of care regardless of cause, since preventing dehydration is what keeps a mild infection from turning serious.
What causes it
Gastrointestinal infection is an inflammation of the stomach and intestines triggered by an invading organism rather than by food alone. Bacteria including Salmonella, E. coli, and Campylobacter are frequent culprits, alongside viruses like norovirus and rotavirus, and less commonly parasites. Contaminated food or water, poor hand hygiene, and close contact with an infected person are the usual routes of transmission.
Symptoms
Diarrhea, nausea, vomiting, and cramping abdominal pain are the defining features, sometimes with fever and general fatigue. Symptoms usually build quickly and settle within a few days as the body clears the infection. Blood in the stool, a high fever, or diarrhea lasting more than 72 hours are signs that need medical review rather than home management.
Treatment
Rehydration is the priority for every case: oral rehydration salts replace the fluids and electrolytes lost through vomiting and diarrhea, and preventing dehydration matters more than treating the infection directly. Most viral and mild bacterial infections clear on their own without antibiotics. When a bacterial cause is confirmed and symptoms are more severe, ciprofloxacin, a broad-spectrum antibiotic, targets the gram-negative bacteria responsible for many gut infections, including travellers' diarrhea.
When to see a doctor
Seek medical attention if there is blood in the stool, a fever above 39°C, signs of dehydration such as reduced urination or dizziness, or diarrhea that persists beyond three days. Infants, older adults, and anyone with a weakened immune system should be assessed sooner, since they dehydrate faster and are more vulnerable to complications.
This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.