Lithiasis is a daily issue in every Urologist’s medical practice. Although Endourology has been rapidly developing and Urologists have acquired more thorough knowledge, only little is known about the role of the stones’ chemical composition. Is it possible to determine from images the composition of calculi? What can the patient’s history imply about the composition of stones? Is it important to determine their composition before treating them? How is a proper calculus analysis performed? When and how should supplements be used in lithiasis? Answers will be given through a discussion with all participants.