This work looks at how basic knowledge of Organic Chemistry acquired in the initial stages of the Pharmacy degree is consolidated for its later application. Tests were conducted among first-, second- and third-year students enrolled, respectively, in the subjects Organic Chemistry, Pharmaceutical Chemistry, and Experimentation in Organic and Medicinal Chemistry, comprising questions on the chemistry knowledge considered to be most fundamental, such as aspects of stereochemistry, acidity and basicity, salt formation, and molecular interaction processes at the physiological level. The tests were conducted in the academic years from 2016-2017 to 2018-2019, so that answers from the same group of students could be collected at different stages of the degree. This allowed us to assess which knowledge students typically consolidated and maintained over two to three academic years, as well as that which proved more difficult to retain. The data obtained also provided some information on the students’ capacities for knowledge integration.