Cao Wu is pungent, bitter, hot and highly toxic, with the effects of warming the menstruation, relieving pain, and dispelling wind and dampness (removing wind and dampness from the body). Cao Wu is made from the dried tuberous roots of the northern aconite. Cao Wu is pungent, bitter, hot and toxic, with the effects of warming the menstruation and relieving pain, dispelling wind and removing dampness. It can be used clinically to treat cold pain in the heart and abdomen (cold pain in the heart, mouth and abdomen), wind-cold-dampness paralysis (paralysis of limbs caused by three evils, wind, cold and dampness,), pain in the joints, pain in cold hernia, and can be used for anesthesia to relieve pain. The size of toxicity of Cao Wu is closely related to the time of decoction, concoction and compounding, so it should be used for a long time and reasonably compounded. Cao Wu has strong toxicity, mainly manifested in the nervous system, cardiovascular system, digestive system, kidney and embryo toxicity. Generally, Cao Wu needs to be concocted before it can be used as medicine, and it should be decocted first and for a long time when it is decocted. Cao Wu is contraindicated in pregnant women, and should not be used together with Psidium guajava, Psidium guajava, Psidium guajava seed, Semen xia, Fructus Pei Mu, Pseudostellariae, Ampelopsis, Smallpox Powder and other medicines. Cao Wu needs to be used by a traditional Chinese medicine practitioner after identification, avoid self-medication to avoid damage.