Qianhu and Chaihu are both bitter and slightly cold in nature, and both have the effect of dispersing wind-heat. Qianhu is the dried root of white-flowered Qianhu of the family Umbelliferae, which is bitter and pungent in flavor, slightly cold in nature, and belongs to the lung meridian. Chaihu is the dried root of Chaihu or narrow-leaved Chaihu of the Umbelliferae family, with a bitter, pungent flavor, slightly cold medicinal properties, and is attributed to the gallbladder, liver, and lung meridians. The leaves of Qianhu are broader and more rounded while those of Chaihu are narrow and sharp, similar to bamboo leaves. Qianhu has the effects of lowering qi, resolving phlegm and evacuating wind-heat. It is mainly used for treating phlegm-heat cough and asthma, wind-heat cough and other diseases. On the other hand, Chai Hu has the efficacy of relieving exterior heat, dispersing the liver and relieving depression (treating depression by dispersing liver qi), and elevating yang qi. People who are allergic to Qianhu and Chaihu should be prohibited from using the drug, and patients with deficiency of qi and blood, and yin deficiency and fire (deficiency of yin and essence in the body, with the appearance of hyperactivity of deficiency fire) should not use Chaihu. Patients need to follow the doctor’s instructions when taking the drug, avoiding private treatment to avoid adverse effects.