Kampo or Kanpō medicine (漢方医学, Kanpō igaku), often known simply as Kanpō (漢方; Chinese medicine), is the study of traditional medicine in Japan following its introduction, beginning in the 7th century. It was adapted and modified to suit Japanese culture and traditions. Traditional Japanese medicine uses most of the Chinese methods, including acupuncture, moxibustion, traditional Chinese herbology, and traditional food therapy.

According to Chinese mythology, the origins of traditional Chinese medicine are traced back to the three legendary sovereigns Fuxi, Shennong and the Yellow Emperor. Shennong is believed to have tasted hundreds of herbs to ascertain their medicinal value and effects on the human body and help relieve people of their sufferings. The oldest written record focusing solely on the medicinal use of plants was the Shennong Ben Cao Jing which was compiled around the end of the first century B.C. and is said to have classified 365 species of herbs or medicinal plants.

Chinese medical practices were introduced to Japan during the 6th century A.D. In 608, Empress Suiko dispatched E-Nichi, Fuku-In and other young physicians to China. It is said that they studied medicine there for 15 years. Until 838, Japan sent 19 missions to Tang China. While the officials studied Chinese government structures, physicians and many of the Japanese monks absorbed Chinese medical knowledge.

In 702 A.D., the Taihō Code was promulgated as an adaptation of the governmental system of China's Tang dynasty. One section called for the establishment of a university (daigaku) including a medical school with an elaborate training program, but due to incessant civil war this program never became effective. Empress Kōmyō (701–760) established the Hidenin and Seyakuin in the Kōfuku-Temple (Kōfuku-ji) in Nara, being two Buddhist institutions that provided free healthcare and medicine for the needy. For centuries to come Japanese Buddhist monks were essential in conveying Chinese medical know-how to Japan and in providing health care for both the elite and the general population.

In 753 A.D., the Chinese priest Jianzhen (in Japanese Ganjin), who was well-versed in medicine, arrived in Japan after five failed attempts in 12 years to cross the East China Sea. As he was blind, he used his sense of smell to identify herbs. He brought medical texts and a large collection of materia medica to the imperial palace in Nara, which he dedicated to the Emperor Shōmu in 756, 49 days after the emperor's death. They are kept in a log-cabin-style treasure house of the Tōdai-Temple (Tōdai-ji) known as Shōsōin.

In 787 A.D., the "Newly Revised Materia Medica" (Xinxiu Bencao, 659 A.D.), which had been sponsored by the Tang Imperial Court, became an obligatory text in the study of medicine at the Japanese Health Ministry, but many of the 844 medicinal substances described in this book were not available in Japan at the time. Around 918 A.D., a Japanese medical dictionary entitled "Japanese names of (Chinese) Materia Medica" (Honzō-wamyō) was compiled, quoting from 60 Chinese medical works.

During the Heian period, Tanba Yasuyori (912–995) compiled the first Japanese medical book, Ishinpō ("Prescriptions from the Heart of Medicine"), drawing from numerous Chinese texts, some of which have perished later. During the period from 1200 to 1600, medicine in Japan became more practical. Most of the physicians were Buddhist monks who continued to use the formulas, theories and practices that had been introduced by the early envoys from Tang China.

During the 15th and 16th centuries, Japanese physicians began to achieve a more independent view on Chinese medicine. After 12 years of studies in China Tashiro Sanki (1465–1537) became the leading figure of a movement called "Followers of Later Developments in Medicine" (Gosei-ha). This school propagated the teachings of Li Dongyuan and Zhu Tanxi that gradually superseded the older doctrines from the Song dynasty. Manase Dōsan, one of his disciples, adapted Tashiro's teachings to Japanese conditions. Based on his own observation and experience, he compiled a book on internal medicine in eight volumes (Keiteki-shū) and established an influential private medical school (Keiteki-in) in Kyōto. His son Gensaku wrote a book of case studies (Igaku tenshō-ki) and developed a considerable number of new herb formulas.