Threadworm

Threadworms are a common type of intestinal worm that can cause itching around the anus, discomfort, and disturbed sleep. While they are easily treated, good hygiene can help prevent re-infection.

Simple measures such as washing hands regularly, keeping nails short, and washing bedding and clothing can reduce the spread.

Through 123Meds, you can receive expert-approved treatments for threadworms via our UK-registered online pharmacy service, with prescriptions reviewed by clinicians and delivered discreetly straight to your door.

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Threadworms (also known as pinworms) are tiny white parasites that infect the large intestine. They’re especially common in young children and often go unnoticed.

The worms look like small white threads and may be visible in stools, or occasionally on bedding or pyjamas.

Many people have no symptoms, but the most common sign is itching around the anus, especially at night. This can disturb sleep and lead to scratching, which may cause skin irritation or infection.

In more severe cases, threadworms can lead to loss of appetite and weight loss.

Threadworms spread easily from person to person. Their eggs are passed in stool and can survive on hands, under fingernails, on bedding, toys or other surfaces.

When someone swallows the eggs, they hatch in the gut. Because the eggs are so small, they can spread quickly in households or schools if good hygiene is not followed.

The most common sign is itching around the bottom or vagina, especially at night. This can disturb sleep. You may sometimes see tiny white worms (like small threads) in stool or around the anus. Other symptoms can include irritability, restlessness, or mild tummy pain.

You should seek medical advice if your child has a fever, abdominal pain that is severe or worsening, blood in the stool, or if the itching does not improve after treatment.

Adults with unexplained weight loss, persistent diarrhoea, or severe symptoms should also contact their GP.

Threadworms are usually treated with a medicine such as mebendazole, which kills the worms but not the eggs. This means that all household members often need treatment at the same time to prevent reinfection.

Good hygiene is just as important as the medicine. Wash hands regularly, keep fingernails short, wash bedding and nightwear in hot water, and clean bathrooms and kitchen surfaces thoroughly.

Our service can provide treatment for uncomplicated threadworm infections in adults. Always read the patient information leaflet that comes with your medicine, and contact a healthcare professional if your symptoms do not improve.

If you develop severe abdominal pain, vomiting, or other concerning symptoms, you should seek urgent medical advice via NHS 111, your GP, or A&E.

Frequently asked questions

What are threadworms and what symptoms should I look out for?
Threadworms, also called pinworms, are tiny white worms that live in the gut. They look like thin pieces of thread. The most common symptom is itching around the bottom at night, but you may also notice restless sleep, irritability, or see worms in stools or around the anus. If you or your child have these symptoms, we can help with quick and effective treatment.
How do you catch threadworms?
Threadworms spread when their eggs are swallowed (usually through contact with contaminated food or surfaces). These eggs can survive on hands, bedding, clothing, toys and surfaces for up to two weeks. They are easily passed around between family members, especially children. If one person in the household is infected, it is very likely that others are too, which is why we recommend treating everyone at the same time.
What is the treatment for threadworms in the UK?
We prescribe mebendazole, the recommended treatment in the UK. It is usually taken as a single tablet or liquid dose and is safe for most adults and children over two years old. We provide guidance on how to take the medicine and when a second dose may be needed. To be most effective, the whole household should be treated together.
Will threadworms go away without treatment?
Threadworms rarely clear up on their own. Without treatment they continue to spread and re-infect the household. By starting treatment with us, along with simple hygiene measures, you can clear the infection effectively and prevent it from coming back.
How can I stop threadworms from returning?
Alongside treatment, hygiene steps are vital. Washing hands often, showering in the morning, keeping nails short, washing bedding and underwear regularly and cleaning frequently touched surfaces all reduce the risk of reinfection. We provide clear aftercare advice to help you keep your household worm-free.