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Giardiasis, or giardia, is an infection of the intestines caused by a parasite. The Giardia parasite lives in the intestines of infected humans or animals. It is most often spread through direct contact. It can also spread through contaminated food or water.



  • Antibiotics: This medicine will help fight the infection.
  • Antiparasitics: This medicine will help kill the parasite that is causing giardiasis.
  • Take your medicine as directed. Contact your healthcare provider if you think your medicine is not helping or if you have side effects. Tell him of her if you are allergic to any medicine. Keep a list of the medicines, vitamins, and herbs you take. Include the amounts, and when and why you take them. Bring the list or the pill bottles to follow-up visits. Carry your medicine list with you in case of an emergency.


  • Drink liquids as directed: You may need to drink extra liquids to help prevent dehydration. Ask how much liquid to drink each day and which liquids are best for you. You may need an oral rehydration solution (ORS). An ORS has the right amounts of water, salts, and sugar your body needs.
  • Eat a variety of healthy foods: Healthy foods include fruits, vegetables, whole-grain breads, low-fat dairy products, beans, lean meats, and fish. You may need to limit the amount of milk products or fat you eat. Ask if you need to be on a special diet.

Prevent giardiasis:

  • Wash your hands often: Use soap and water. Wash your hands after you use the bathroom, change a child's diapers, or sneeze. Wash your hands before you prepare or eat food.
  • Wait to have sex: Wait until your signs and symptoms are gone before you have sex. Use protection when you have sex.
  • Drink safe water: Drink only sealed, bottled water or carbonated water. Do not drink water from streams, rivers, or lakes. Boil water or treat it with a chemical purifier to make it clean and safe.
  • Handle food properly: Cook food to the proper temperature. Do not eat raw food. Wash your fruits and vegetables with clean water or peel them before you eat them.

Follow up with your doctor as directed:

Write down your questions so you remember to ask them during your visits.

Contact your healthcare provider if:

  • Your signs and symptoms last more than 1 week.
  • You have questions or concerns about your condition or care.

Return to the emergency department if:

  • You are dizzy and weak.
  • You have a dry mouth, cracked lips, and feel thirsty.
  • You have a fast heartbeat and are breathing fast.
  • You urinate less than usual or not at all.
  • You have severe abdominal pain or your abdomen is hard and swollen.
  • You have black or bright red bowel movements.
  • Your vomit has blood in it.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

Learn more about Giardiasis (Aftercare Instructions)

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Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.