If you have intestinal parasites, you may have digestive symptoms, including abdominal pain and diarrhea. Untreated, worms may cause complications. Intestinal worms, also known as parasitic worms, are one of the main types of intestinal parasites in humans. They’re most commonly found in subtropical and tropical regions, but some types are found in the United States. Most intestinal worm infections only cause mild illness and can be treated with medication. Read on to learn more about intestinal