Radix Isatidis is more suitable for wind-heat cold caused by internal heat evil because of its bitter and cold taste. People who usually have a hot constitution can also drink a bag of Radix Isatidis granules after breakfast and dinner to prevent it, but it is best not to exceed three days. If people who have a weak constitution and cold often feel disharmony between spleen and stomach, are prone to diarrhea and are afraid of cold, it is not appropriate to drink more Radix Isatidis granules. Because of its bitter cold, it will bring a series of gastrointestinal reactions, which will lead to a cold that is not cured, but will cause stomach pain, chills, loss of appetite and other symptoms, especially children.