The Practica medicinae represented the books written in Europe before the end of 18th century that dealt with individual deseases. In total, 100 Practica books, written by 95 authors, were collected and divided into four periods from the early 11th to the end of 18th century. The first Practica book was written at the Salernitan medical school on the basis of ancient medical books in the basic style, dealing with regional deseases arranged in "a capite ad calcem" manner, as well as with the fevers. The basic style comprised a majority in the first period and decreased gradually, becoming a minority in the 3rd and 4th periods. Sennert's practica was the largest and it elaborated with precise construction. The additional categories, such as female, children, and surgical deseases increased in the later periods. Those written in non-basic style based on pathogenesis or in alphabetical order also increased in the later periods. The practica books changed slightly and gradually, indicating the essential consistency of the concepts of diseases in these periods.