Diagnosis

Diagnosis of ascariasis involves a healthcare checkup to find out if the infection is the cause of your symptoms. Your healthcare professional asks you about your symptoms and may order tests.

If you have many roundworms in your body, you may see some after you cough or vomit. The worms can come out of other body openings, such as your nostrils. If this happens to you, take the worm to your healthcare professional. That way, your healthcare professional can identify the worm and make sure you get the right treatment.

Stool tests

Mature female ascariasis worms in the small intestine start laying eggs. In time, these eggs can be found in the stool.

Your healthcare professional checks your stool for the tiny eggs and larvae. But eggs won't appear in stool until at least 40 days after you're infected. And if you're infected with only male worms, you won't have eggs in your stool.

Blood tests

Blood tests can check for a higher than usual number white blood cells called eosinophils. Ascariasis can raise your eosinophil level, but so can other health conditions.

Imaging tests

  • X-rays. If you have worms inside your body, an X-ray of the stomach area may show a mass of the parasites. Sometimes, a chest X-ray can reveal the larvae in the lungs.
  • Ultrasound. An ultrasound may show worms in the pancreas or liver. This test uses sound waves to make images of internal organs.
  • Computerized tomography (CT) scans or magnetic resonance imaging (MRI). Both types of tests create detailed images inside the body. The images can help your healthcare professional find worms that are blocking ducts in the liver or pancreas. CT scans combine X-ray images taken from many angles. MRI uses radio waves and a strong magnetic field.

Treatment

Ascariasis treatment usually involves taking medicine. Sometimes surgery is needed.

Medications

Anti-parasite medicines can help the body get rid of roundworms that cause ascariasis. The most common medicines are:

  • Albendazole.
  • Mebendazole (Emverm).
  • Ivermectin (Stromectol).

These medicines kill the adult worms in the small intestine. Albendazole and ivermectin are taken once. Mebendazole is taken once in a large dose or twice a day for three days in smaller amounts. Side effects can include mild stomach pain, headache and diarrhea.

Pregnant people may take an anti-parasite medicine called pyrantel pamoate.

Surgery

If many worms are in the body, sometimes surgery is needed to remove worms and repair damage they've caused. Intestine blockage or holes, bile duct blockage, and appendicitis are complications that may require surgery.


Preparing for your appointment

Your family healthcare professional might refer you to a doctor called a gastroenterologist, who is trained in digestive conditions. You may need to see a surgeon if the worms have blocked the intestines.

What you can do

Before your appointment, you may want to write down the answers to the following questions:

  • When did your symptoms start?
  • Does anything make your symptoms better or worse?
  • Have you noticed worms in your stool or vomit?
  • Have you traveled to developing countries lately?
  • What medicines and supplements are you taking?

What to expect from your doctor

During the physical exam, your healthcare professional may press on parts of the stomach area to check for pain or tenderness. Your healthcare professional also may want a sample of stool for testing.


July 24, 2025

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  2. Parasites — Ascariasis. Centers for Disease Control and Prevention. https://www.cdc.gov/parasites/ascariasis/. Accessed Feb. 13, 2024.
  3. Ascariasis. Merck Manual Professional Version. https://www.merckmanuals.com/professional/infectious-diseases/nematodes-roundworms/ascariasis. Accessed Feb. 13, 2024.
  4. Ferri FF. Ascariasis. In: Ferri's Clinical Advisor 2024. Elsevier; 2024. https://www.clinicalkey.com. Accessed Feb. 13, 2024.
  5. Kellerman RD, et al. Intestinal parasites. In: Conn's Current Therapy 2024. Elsevier; 2024. https://www.clinicalkey.com. Accessed Feb. 13, 2024.
  6. Roundworm infection. AskMayoExpert. Mayo Clinic; 2023.
  7. Medical review (expert opinion). Mayo Clinic. Feb. 15, 2024.

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