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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.

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.

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.

Non-urgent advice: 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.

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.


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.