EU citizens ― persons who reside on the territory of Poland temporarily are entitled to use free medical services pursuant to the European Health Insurance Card (EHIC). However, it is advisable to take out a separate accident insurance.
National Health Fund - https://www.ekuz.nfz.gov.pl
Non-EU citizens ― Before coming to Poland, every student should arrange health insurance (e.g. Euro26 or Isic). According to domestic regulations concerning medical care, citizens from outside EU are obliged to bear the costs related to medical services. Such costs are later covered by their insurers.