Prepared Caowu (processed Aconitum kusnezoffii root) is a traditional Chinese medicinal material made from Caowu through processing to reduce its toxicity.

Prepared Caowu is the processed product of the Chinese herbal medicine Caowu, whose original plant is Aconitum kusnezoffii and other species of the genus Aconitum in the Ranunculaceae family, and whose medicinal part is the dried tuberous root. Raw Caowu is highly toxic and cannot be taken internally directly; it must undergo standardized processing to become Prepared Caowu before it can be used in prescriptions.

In the traditional processing method, Caowu is generally first sorted by size, soaked in clean water until no dry core remains inside, then boiled in water until, when cut open, there is no white core and a slight numbing sensation is felt on tasting, at which point it is removed, air-dried until half dry, sliced and dried. In some regions, auxiliary materials such as licorice and black beans are also added and boiled together to further reduce toxicity.

Prepared Caowu is pungent and bitter in taste and hot in nature, with the effects of dispelling wind and removing dampness and warming the meridians to relieve pain. It is often used for wind-cold-dampness arthralgia, joint pain, cold pain in the chest and abdomen, and cold hernia pain, and has also been used in combination for anesthesia and analgesia. It is similar in origin to Prepared Chuanwu, and Caowu is generally considered to have a stronger action in dispelling wind and relieving pain.

It should be noted that although Prepared Caowu has undergone toxicity-reducing treatment, it still belongs to the toxic medicinal materials, and the dosage must be strictly controlled when used; when decocted in a decoction, it is generally required to be decocted first and for a long time. It is contraindicated in pregnant women and should not be used together with Banxia, Gualou, Beimu, Bailian, and Baiji. One must never dig up and take Caowu on one's own; medication must always be taken under the guidance of a Chinese medicine practitioner to prevent poisoning.