Drinking kale does not usually cause diarrhea, but it can cause diarrhea if there are problems with the quality of hygiene.
Kale is an edible biennial herb, also known as flower cabbage, green leaf kale, etc., is widely used in ornamental plants, but also part of the people like its flavor and used to grind brew drink off, as an edible plant, in general, drinking kale will not lead to diarrhea, can be digested normally.
However, if the edible kale itself has health quality problems, such as the presence of insects, sewage pollution, mold, rot, etc., after drinking it will lead to acute gastroenteritis, causing abdominal pain, nausea, vomiting, diarrhea and other symptoms, but this has nothing to do with the nature of the kale itself.