In November 2022, the third chamber of the Supreme Court of Chile issued three rulings in different writs of mandamus, with effects regarding all contributors to the private health system (Isapre). This work aims to contribute to the discussion that these decisions have motivated from the science of procedural law, reviewing in general terms the nature of the writ of mandamus, what is the effect of res judicata generated by its decisions, the problems of concurrent procedures, and the erga omnes effects of their rulings