Skip to content

Giardiasis

Giardiasis is an intestinal infection caused by Giardia. It spreads when microscopic cysts from faeces contaminate water, food, hands or surfaces, and it can cause prolonged diarrhoea and poor nutrient absorption.

Tinidazole Tablets

Tinidazole

500mg

Tinidazole 500mg tablets, used for giardiasis, trichomoniasis and anaerobic bacterial infection. It breaks DNA strands in susceptible organisms.

From$0.55/ tabletView

Ornidazole Tablets

Ornidazole

500mg

Ornidazole 500mg tablets, used for trichomoniasis, amoebiasis and giardiasis. A nitroimidazole that disrupts DNA synthesis in protozoa.

From$0.98/ tabletView

Albenza

Albendazole

400mg

Albendazole 400mg tablets, used for helminthiasis, giardiasis and parasitic worm infection. A benzimidazole that degrades microtubules in parasite cells.

From$0.47/ tabletView

Key points

  • Greasy, foul-smelling diarrhoea, bloating and excessive wind are typical clues, but stool testing may be needed for confirmation.
  • Rehydration matters, while an antiparasitic medicine is chosen according to diagnosis, pregnancy, interactions and prior treatment.
  • Persistent symptoms after treatment may reflect reinfection, incomplete clearance or temporary lactose intolerance rather than automatic treatment failure.

An antiparasitic listing cannot identify the cause of diarrhoea; symptoms, exposures and test results determine whether treatment is appropriate.

How is giardiasis recognised?

Symptoms may begin gradually and include floating or greasy stools, cramps, nausea, fatigue and weight loss. Fever and bloody diarrhoea are less typical and may point to another infection. One stool sample can miss the parasite, so repeated or antigen-based testing may be used.

What does treatment involve?

Tinidazole, ornidazole and albendazole are among medicines used in selected cases. They differ in suitability and interactions. Safe water, handwashing and avoiding food preparation while symptomatic can reduce spread. See antiparasitics for class context.

When to seek urgent care

Seek urgent help for inability to keep fluids down, very little urine, fainting, marked drowsiness, blood or black stool, severe localised abdominal pain or high fever. Infants and people who are frail or immunocompromised need earlier review.

Further reading