To diagnose ascariasis, your doctor may review your symptoms and order tests.

In heavy infestations, it's possible to find worms after you cough or vomit. The worms can come out of other body openings, such as your mouth or nostrils. If this happens to you, take the worm to your doctor so that he or she can identify it and prescribe the proper treatment.

Stool tests

Mature female ascariasis worms in your intestine begin laying eggs. These eggs travel through your digestive system and eventually can be found in your stool.

To diagnose ascariasis, your doctor will examine your stool for the tiny (microscopic) 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.

Blood tests

Your blood can be tested for the presence of an increased number of a certain type of white blood cell, called eosinophils. Ascariasis can elevate your eosinophils, but so can other types of health problems.

Imaging tests

  • X-rays. If you're infested with worms, the mass of worms may be visible in an X-ray of the abdomen. In some cases, a chest X-ray can reveal the larvae in the lungs.
  • Ultrasound. An ultrasound may show worms in the pancreas or liver. This technology uses sound waves to create images of internal organs.
  • computed tomography (CT) scans or Magnetic resonance imaging (MRI)s. Both types of tests create detailed images of the internal structures, which can help your doctor detect 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.


Typically, only infections that cause symptoms need to be treated. In some cases, ascariasis will resolve on its own.


Anti-parasite medications are the first line of treatment against ascariasis. The most common are:

  • Albendazole (Albenza)
  • Ivermectin (Stromectol)
  • Mebendazole

These medications, taken for one to three days, kill the adult worms. Side effects include mild abdominal pain or diarrhea.

Pregnant women may take pyrantel pamoate.


In cases of heavy infestation, surgery may be necessary to remove worms and repair damage they've caused. Intestinal blockage or holes, bile duct blockage, and appendicitis are complications that may require surgery.

Preparing for your appointment

Your family doctor might refer you to a doctor trained in digestive disorders (gastroenterologist). 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 begin?
  • 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 medications and supplements are you taking?

What to expect from your doctor

During the physical exam, your doctor may press on certain areas of the abdomen to check for pain or tenderness. He or she may also want a sample of stool for testing.

May 17, 2022

  1. Leder K, et al. Ascariasis. https://www.uptodate.com/contents/search. Accessed April 30, 2020.
  2. Parasites — ascariasis. Centers for Disease Control and Prevention. https://www.cdc.gov/parasites/ascariasis/. Accessed May 1, 2020.
  3. Ascariasis. Merck Manual Professional Version. https://www.merckmanuals.com/professional/infectious-diseases/nematodes-roundworms/ascariasis?query=ascariasis. Accessed May 1, 2020.
  4. Elsevier Point of Care. Clinical Overview: Ascariasis. https://www.clinicalkey.com. Accessed May 1, 2020.
  5. Kellerman RD, et al. Parasitic diseases of the skin. In: Conn's Current Therapy 2020. Elsevier; 2020. https://www.clinicalkey.com. Accessed May 1, 2020.


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