Giardiasis is a tummy bug that causes symptoms like diarrhoea, farting and bloating. It usually goes away in about a week if it's treated, but can sometimes last much longer.

How giardiasis is spread

There are lots of ways you can catch giardiasis, such as:

  • drinking water that's not been treated to kill germs (usually while travelling in developing countries)
  • water getting in your mouth while swimming in places like lakes, rivers or swimming pools
  • eating food that's been washed in untreated water or handled by someone with the infection
  • touching surfaces that have been touched by an infected person
  • having sex – especially unprotected anal sex

You can become infected if small bits of poo from an infected person get in your mouth.

Symptoms of giardiasis

The main symptoms of giardiasis are:

  • smelly diarrhoea
  • tummy pain or cramps
  • farting (flatulence)
  • smelly burps – they may smell like eggs
  • bloating
  • weight loss

You can also have it and be able to spread it to others without having any symptoms.

Call your GP surgery or 111 if:

  • you have had diarrhoea for more than a week
  • you have bloody diarrhoea or bleeding from your bottom

It's best to call rather than visit a GP surgery as you might have an infection that can spread easily to others.

Tell the GP if you have recently travelled abroad.

Treatment for giardiasis

Your GP may send off a sample of your poo for tests to check if you have giardiasis.

It's treated with antibiotics for a few days. Your symptoms should stop in about a week, but they can sometimes last longer.


Go back to a GP if you still have symptoms a week after starting treatment.

They might give you more antibiotics or refer you to a specialist for treatment.

Sometimes the people you live with may also need to be tested and treated.

How to look after yourself if you have giardiasis


You're most infectious from when your symptoms start until 2 days after they have passed.

Stay off school or work until your symptoms have stopped for 2 days.

While you're recovering:


  • drink lots of fluids to avoid dehydration, such as water and squash – if you're well hydrated, your pee should be light yellow or clear

  • give your baby breast or bottle feeds as usual if you or your baby are ill

  • wash your hands with soap and water frequently

  • wash dirty clothing and bedding separately on a hot wash

  • clean toilet seats, flush handles, taps, surfaces and door handles every day


  • do not drink alcohol while taking your antibiotics – alcohol can react with the main antibiotics used to treat giardiasis

  • do not prepare food for other people, if possible

  • do not share towels, wash cloths, flannels, cutlery and utensils

  • do not use a swimming pool until 2 weeks after your symptoms stop

A pharmacist can help if you're dehydrated

Speak to a pharmacist if you have signs of dehydration, such as peeing less than usual or having dark, strong-smelling pee.

They may recommend using sachets that you mix with water to help you stay hydrated, called oral rehydration solutions.

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