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Roundworm infections can be successfully treated using medicine.

The 3 main medicines are:

  • mebendazole
  • piperazine
  • albendazole


Mebendazole is recommended for treating roundworm infections in adults and children over 1 year old.

It works by stopping the roundworms using glucose (sugar). Without glucose, the cells of the roundworms lose their energy supply and quickly die.

A 3-day course of mebendazole is usually recommended. This involves taking 1 tablet twice a day.

Stomach pain is the most common side effect of mebendazole.

Less common side effects include:


Piperazine is recommended for babies aged 3 to 11 months. It's available as a powder that you dissolve in water. Most children only need a single dose.

Side effects of piperazine can include:

  • stomach pain
  • nausea and vomiting 
  • colic (excessive, frequent crying) 
  • diarrhoea

These side effects should pass quickly once the medicine works its way out of the body.

If your child is less than 3 months of age, delaying treatment until they reach 3 months may be recommended.


Albendazole is commonly used in tropical countries, but is currently unlicensed for use in the UK.

This means the medicine's manufacturer has not applied for a license for albendazole to be used to treat roundworm in the UK. However, it's been extensively studied in countries where roundworm is common, and has been shown to be safe and effective.


While there's no firm evidence to suggest that any of the medicines used to treat roundworm can cause birth defects, they're not usually recommended during pregnancy.

Roundworms can occasionally cause troublesome symptoms, but they do not usually pose a threat to your unborn child.