Folk medicine, studied by ethnographers since the nineteenth century, is a part of folk culture and can only be investigated in its context. The article aims to depict how the presence of ethnomedicine is reflected in language on the level of the lexical system, and specifically in the dialect names of diseases. The author focused on just one group of names influenced by cultural factors, i.e. names determined by folk etiological beliefs. This category of names was discussed using the following examples: miesięcznik – the name of a children’s disease, boża kara, boża wola ‘epilepsy’, poszedło – a Kashubian name of epidemic infectious diseases, names connected morphologically with the verb strzelać, wąsak and related forms meaning ‘pain in the lower back’.