Thyroid nodules do not cause changes in the frequency of bowel movements because of the swelling of the growing thyroid gland. Benign ones may have only atypical hyperplasia or no changes, signs and symptoms at all. Malignant thyroid nodules are mainly pre-invasive involving the thyroid gland as well as the surrounding nerves and may have infiltrative growth. Breakthrough into the hypotrachea or compression of the esophagus and nerves by larger glands leads to difficulty swallowing and hoarseness, but does not lead to changes in the nature or frequency of bowel movements. If the number of stools increases abnormally, gastrointestinal diseases are considered to be more likely. For example, the presence of gastroenteritis, colitis, or inflammation of the rectum or anal canal may lead to an increase in the number of bowel movements. In addition, malignant tumors of the intestinal tract, especially those of the large intestine, often lead to an increase in the number of bowel movements, and may be accompanied by irregular bowel movements, thinning of the bowel movements or blood in the stool. Therefore, if there is a change in the nature of bowel movement for a long time, it is recommended to have an electronic colonoscopy to confirm the diagnosis.