What should you know about what causes giardiasis?

After entering the body, Giardia settles in the small intestine. It may disturb digestion and lead to watery or greasy diarrhoea, gas, bloating, cramps and nausea. A person may carry and pass the parasite without realising it. A symptom such as [Abdominal Pain](/symptoms/abdominal-pain/) has many possible causes, so it does not by itself prove giardiasis. Read about [Giardiasis](/conditions/giardiasis/) and [Diarrhoea](/symptoms/diarrhoea/).

Wash hands with soap and water after using the toilet, changing nappies and before eating or cooking. Use safe drinking water, wash fresh produce, and avoid sharing towels during illness. Clean frequently touched bathroom surfaces. If you develop symptoms, arrange a [GP Consultation](/treatments/consultations-and-assessment/gp-consultation/) and mention travel, untreated water or an affected household member. Do not start [Antibiotic Treatment](/treatments/medical-management/antibiotic-treatment/) without medical advice.

Get urgent help for fainting, confusion, severe weakness, inability to drink, very little urine, blood in stools or intense abdominal pain. Arrange prompt assessment if diarrhoea persists, a child is affected, or you have a condition or medicine that weakens immunity. Ongoing symptoms can require testing and treatment rather than home care alone.

Ask how the infection might have been acquired, whether close contacts need advice, how long to take precautions, and whether stool testing is appropriate. Tell the clinician about recent travel, camping, untreated water and similar illness at home.