Purple kale does not usually cause a positive fecal occult blood test, and positive occult blood results have been associated with gastrointestinal bleeding, hemorrhoids, and ulcerative colitis. Fecal occult blood test, also known as fecal occult blood test, is a commonly used clinical laboratory method to test the feces can not be seen with the naked eye, trace amounts of blood, the diagnosis of gastrointestinal bleeding has an important value, but also the digestive tract is also an important screening index for early diagnosis of malignant tumors. Pathologically positive results can also be seen in positive intestinal tuberculosis, ulcerative colitis, colon polyps, gastrointestinal tumors, chronic blood loss and so on. However, eating chlorophyll-containing foods, animal blood products, and iron medications in the days prior to the fecal occult blood test can lead to a false-positive result. Purple kale does not cause a positive fecal occult blood test. To summarize, it is best not to consume chlorophyll-containing foods, animal blood products, etc. before performing a fecal occult blood test so as not to affect the test results.