ENThe article dwells on the specific features of the sanitary practices (i. e. pracrices related to health, aimed at preserving healthy body) performed in the Jesuit collegiums of the Grand Duchy of Lithuania in the XVI-XVIII centuries. The information presented in the article is based on (and quotes) documents from order archives, clauses from Jesuit order regulations and narrative sources created by Jesuits. The article focuses not on personalities, but mainly on system-making principles and elements. Being aware of them enables better understanding and adequate interpretation of the way personalities acted in the historical perspective and the was health care structures of collegiums responded to everyday situations and emergencies. Keywords: Grand Duchy of Lithuania, the Society of Jesus, Jesuits, collegium, doctor, infirmary, pharmacist, health, epidemic.