Poland has a healthcare system based on general health insurance. Persons covered by the general health insurance are entitled to free health services in Poland at the health care providers who have signed contracts with the National Health Fund (NFZ – Narodowy Fundusz Zdrowia).
The National Health Fund is the institution, responsible for coordination of health services for insured persons. Erasmus+ students holding UKW student card are advised to use the services of the academic healthcare centre in Bydgoszcz (Przychodnia Akademicka, Bydgoszcz, 9 Kołłątaja Street). If it is urgent and you do mind paying for a visit you can go private. In that case it is recommended this website: https://www.znanylekarz.pl/
In need of medical care, Erasmus+ student from EU country is entitled to free healthcare, based on the European Health Insurance Card (EHIC). The student is obliged to present EHIC (it is advisable to have also a copy) together with an identity document to the public health care provider. Students from the European Union or the European Economic Area are expected to apply for the European Health Insurance Card (EHIC) in their home country.
Students from outside the European Union and EEA countries are obliged to obtain the health insurance either at the Polish National Health Fund (NFZ) after coming to Poland or at any other private insurance company in their home country or in Poland. The health insurance must be valid throughout the whole period of your stay in Poland. Depending on the terms and conditions of your insurance, you can receive health care free of charge, or you will be charged and get the costs of the treatment reimbursed after coming back home.
Further read:
Erasmus blog Bydgoszcz, Poland | Erasmusu.com (some information, especially those concerning prices may be a little outdated)