Although Radix Isatidis has preventive effect on some common diseases, as a medicine, it also has certain toxic and side effects when used too much. When the detoxification ability of human liver declines, taking Radix Isatidis for a long time and in large doses will cause accumulation poisoning, harm human digestive system and hematopoietic system, and easily lead to upper respiratory bleeding and leukopenia.

In addition, Radix Isatidis belongs to the medicine of sexual cold, which has a good effect on preventing and treating the symptoms of excess heat. However, for those patients with spleen and stomach deficiency and cold, taking Radix Isatidis often will cause their symptoms such as pale mouth and fatigue, resulting in physical decline, which will not only fail to prevent diseases, but will cause diseases.