Giardiasis

Request an online visit for Giardiasis. A licensed provider reviews your case and prescribes treatment when appropriate.

Medically reviewed by Dr. Ikechukwu Ogbu, MD
MD · Board-Certified, Internal Medicine · Last reviewed June 2026

About Giardiasis

Giardia duodenalis is a protozoan parasite acquired from contaminated water, food, or fecal–oral contact. It causes prolonged watery or greasy diarrhea, abdominal cramps, bloating, malabsorption, fatigue, and weight loss; some carriers remain asymptomatic. Risk is higher with international travel, camping, day-care attendance, and certain water exposures. Diagnosis is by stool antigen or PCR. Treatment is oral tinidazole, metronidazole, or nitazoxanide. Persistent symptoms after treatment may reflect post-infectious irritable bowel syndrome or lactose intolerance rather than treatment failure.

Common questions

Reference only. Not a substitute for medical advice. Not appropriate for emergencies or controlled substances.