Giardiasis is an intestinal infection caused by the parasite Giardia. You may become infected by having contaminated food or water. Exposure to the stool of someone who`s infected can also cause infection.

When to call the healthcare provider

Call your healthcare provider for severe symptoms that include:

  • Diarrhea

  • Stomach bloating or fullness

  • Upset stomach (nausea) or vomiting

  • Unplanned weight loss

  • Blood in your stool

  • Dehydration

When to call 911

Call 911 if you have: 

  • Uncontrolled vomiting

  • Severe belly pain

What to expect at the healthcare provider's office

You will be examined and will likely have a stool sample checked in a lab. This stool is checked for the parasite that causes the disease. If giardiasis is suspected or confirmed, you may be prescribed medicine that you take for 5 to 7 days. In many cases, this clears the infection.

Preventing giardiasis

Closeup of woman washing hands in sink.
Giardiasis is an intestinal infection caused by the parasite Giardia

Take these steps to help prevent infection with Giardia:

  • Wash your hands with clean, running water (warm or cold) after using the bathroom and before eating. Wash for at least 20 seconds. Alcohol-based hand sanitizers may not work against Giardia.

  • Wash your hands each time you change a child's diaper.

  • Don't drink from rivers and streams.

  • Use a water treatment kit when camping. 

  • Wash or peel raw fruits and vegetables before using.

© 2000-2024 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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