saudigastro.com/patients/intestinal-parasites
Category
Common
Red flags
5
This article is educational and does not replace your doctor's advice. Seek urgent care for any red-flag symptoms.
What is it?
Intestinal parasites include single-celled organisms such as Giardia, and worms such as roundworm, pinworm, hookworm, whipworm and tapeworm. They live in the intestines and take nutrients from the body or irritate the bowel. Different parasites cause different symptoms, and some people have no symptoms at all.
How common is it?
These infections are found worldwide and are more common where clean water and sanitation are limited, in crowded settings, and among young children. Pinworm is common in children everywhere, including in settings with good sanitation.
Why does it happen?
Infection usually happens by swallowing eggs or cysts from contaminated food, water, soil or hands, or by eating undercooked meat or fish that contains parasite larvae. Some worms, such as hookworm, enter through the skin when walking barefoot on contaminated soil. Poor hand washing, especially in children, spreads infection within families and schools.
Symptoms
- Diarrhea, loose stools or greasy, foul-smelling stools
- Abdominal pain, cramps, bloating and gas
- Nausea and poor appetite
- Itching around the anus, worse at night (typical of pinworm)
- Weight loss, tiredness or paleness from anemia (low red blood cells)
- Seeing worms or segments in the stool
Red flags — seek urgent medical care
Severe or constant abdominal pain with vomiting and a swollen belly
A heavy worm load can occasionally block the bowel. Go to the emergency department.
Vomiting a worm or coughing one up
Needs prompt medical assessment.
Persistent diarrhea with dehydration, especially in a baby or young child
A baby or child with dehydration must be seen urgently.
Marked paleness, breathlessness or dizziness
May indicate significant anemia from blood loss in the gut; see a doctor soon.
Fever, seizures, or severe headache after eating undercooked meat
Some tapeworm larvae can reach other organs, including the brain. Seek urgent care.
How is it diagnosed?
Diagnosis is usually by examining stool samples under the microscope or with special stool tests for the parasite; more than one sample may be needed. Pinworm is often found with a tape test around the anus in the morning. Blood tests may show anemia or raised eosinophils (a type of white blood cell that rises with some parasites). Imaging or endoscopy is only used in selected cases.
Outlook — what to expect
Most infections clear completely after the right treatment. Re-infection is common if hygiene and the source of exposure do not change, so household measures are important, and in some cases the whole family is treated together.
Treatment
Habits & Lifestyle
Hygiene is the most effective prevention.
- Wash hands with soap and water after the toilet, after changing diapers, and before eating or cooking.
- Keep children's nails short and discourage nail biting and thumb sucking.
- For pinworm, wash bedding, underwear and towels in hot water and shower in the morning.
- Wear shoes outdoors in areas with contaminated soil.
Diet
Safe food and water handling prevents most infections.
- Drink safe, treated or boiled water.
- Wash and peel fruit and vegetables; wash salad leaves carefully.
- Cook meat and fish thoroughly, and avoid raw or undercooked meat.
- Eat iron-rich foods and have your iron checked if anemia is found.
Medications
Anti-parasitic medicines are effective, but the right one depends on the parasite.
- Your doctor will choose the medicine, dose and duration after identifying the parasite.
- For some worms such as pinworm, a repeat course after a couple of weeks and treating the household may be advised.
- Do not use over-the-counter or herbal "worm cleanses" in place of medical treatment.
- Pregnant women and young children need medicines chosen specifically for them; always ask a doctor first.
- Iron supplements may be given for anemia.
Procedures & Surgery
Procedures are rarely needed.
- Endoscopy or colonoscopy may be done if the cause of symptoms is unclear, and sometimes a worm is seen and removed.
- Bowel blockage or complications in the bile ducts from heavy worm infection may need hospital care and sometimes endoscopic or surgical treatment.
Living with the condition
- Repeat stool tests if symptoms return or if your doctor asks for a check after treatment.
- Tell the school or nursery if a child is infected so that hygiene can be reinforced.
In the Saudi context
Travel, workers living in shared accommodation, and eating raw salad or undercooked food away from home can increase exposure. Washing produce and using safe water is advised.
Questions to ask your doctor
Save this list or print it before your appointment — doctors appreciate prepared patients.
- Which parasite do I have, and which medicine is right for it?
- Does my family need treatment or testing?
- Do I have anemia or low iron because of this infection?
- Do I need a repeat stool test after treatment?
- How can I prevent re-infection at home and school?
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Status: Approved for publication by SGA; individual clinician review is ongoing · Published 24/04/2026
For general education only; it does not replace your doctor’s advice. Individual clinician review of this guide is ongoing. SGA clinician? Review this guide