What is the first treatment tried for giardiasis?

Giardiasis is caused by a parasite affecting the digestive system. A clinician may ask about diarrhoea, cramps, bloating, travel, untreated water, and household illness, then request a stool sample. The chosen medicine depends on your symptoms, medical history, pregnancy status, and local prescribing practice. [Antibiotic Treatment](/treatments/medical-management/antibiotic-treatment/) should be taken exactly as prescribed.

Drink frequent small amounts of fluid, and consider oral rehydration advice if diarrhoea is heavy. Wash hands thoroughly after using the toilet and before preparing food; avoid sharing towels. Stay away from swimming while diarrhoea continues. A [GP Consultation](/treatments/consultations-and-assessment/gp-consultation/) can help decide whether testing or treatment is needed and whether close contacts need advice.

Seek prompt care if you cannot keep fluids down, feel faint, pass very little urine, have blood in stool, severe abdominal pain, high fever, or diarrhoea that is not settling. Babies, older adults, pregnant people, and anyone with a weakened immune system may need earlier assessment.

Ask whether a stool test is needed, which medicine fits your health history, how to replace lost fluids, and when you can return to work, school, swimming, or food preparation. Check what to do if symptoms continue after the prescription ends.