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Giardiasis

Giardiasis is an intestinal infection caused by the parasite Giardia. You are most likely to be exposed to Giardia from contaminated water during a camping trip, international travel, or from drinking well-water. You may also become infected by eating contaminated undercooked food. Exposure to the stool of someone who`s infected can also cause infection. A distinctive and classic symptom of Giardia is eruptions (or burps) that smell like sulfur.

When to call your doctor

Call your health care provider if you have:

  • Diarrhea, which often comes and goes.

  • 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.

How is giardiasis treated?

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 will be prescribed an antibiotic that you take for 5 to 7 days. In many cases, this clears the infection.

Preventing giardiasis

Woman washing hands in sink.
Lávese las manos con frecuencia para ayudar a prevenir la infección por 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.

Online Medical Reviewer: Barry Zingman MD
Online Medical Reviewer: Marianne Fraser MSN RN
Online Medical Reviewer: Sabrina Felson MD
Date Last Reviewed: 1/1/2025
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