Boots WebMD Partners in Health
Return To Boots

Digestive health centre

Roundworm - Symptoms of a roundworm infection

NHS Choices Medical Reference

NHS Choices Logo

In most people, a roundworm infection does not cause any noticeable symptoms.

When symptoms occur, they usually follow a two-stage course:

  • Early-phase symptoms are caused by the larvae (newly hatched worms) moving from the small intestine to the lungs. It is unclear why some people develop these symptoms while others do not. 
  • Late-phase symptoms are caused by adult worms living in the intestine. They cannot reproduce inside you. There will only be as many as the eggs you first ingested (see causes of roundworm infection  for more information about the life cycle of the roundworm).

Early-phase symptoms

The early-phase symptoms of a roundworm infection affect only a small proportion of those affected and are rare in the UK. They usually begin four to 16 days after swallowing the eggs and last up to 3 weeks. They include:

  • high temperature (fever) of 38C (100.4F) or above
  • a dry cough
  • shortness of breath
  • wheezing

Late-phase symptoms

The late-phase symptoms are even more rare in the UK, especially in adults.  If there are a lot of mature worms in the intestine they can cause blockages.  This will not occur before six weeks after the eggs have been swallowed.

Signs and symptoms associated with mature worms include:

  • passing a worm in your faeces
  • mild abdominal (tummy) pain
  • nausea
  • vomiting
  • diarrhoea (you may also notice blood in your stools)

(Most people have no symptoms).

Signs and symptoms associated with an intestinal blockage due to a large number of worms include:

  • severe abdominal pain
  • vomiting
Medical Review: August 11, 2012
Next Article:

Mind, body & soul newsletter

Looking after your health and wellbeing.
Sign Up Now!

WebMD Video: Now Playing

digestive disorders

Digestive disorders

Learn what triggers IBS and how to manage symptoms, including diarrhoea and bloating.

Popular Slideshows & Tools on Boots WebMD

woman looking at pregnancy test
Early pregnancy symptoms
donut on plate
The truth about sugar addiction
woman holding hair
Natural help for dry or damaged hair
woman in bikini
Get ready for swimsuit season
hand extinguishing cigarette
13 best tips to stop smoking
Immune-boosting foods
The role of diet
79x79_not_good_for_you.jpg
18 secrets men want you to know
boy looking at broccoli
Quick tips for feeding picky eaters
hamburger and fries
A guide for beginners
salmon dinner
A diet to boost your mood & energy
polka dot dress on hangar
Lose weight without dieting