Purpose Deconstructing current definitions of “health literacy (HL)” and “eHealth literacy (eHL)”, into the core notion of “understanding health information (HI)”, this study provides insights into what promotes and inhibits the understanding of HI for breast cancer patients during cancer patient pathways (CCP) in Norway. Methods Seven well-educated women were interviewed. Through a stepwise deductive-inductive analysis of the transcribed interviews, the following topics were identified: 1) explanations accompanied by drawings, 2) individualized knowledge-based information, 3) information processing capacity, and 4) ambiguity in medical information. Results The women's understanding of HI increased when spoken communication was accompanied by visual illustrations, which served as roadmaps throughout the CPP. Even if HI should be targeted to the patients’ individual needs, some HI can be generalized if it refers to established knowledge about the health phenomena. The women described their changing mental and physical status during the CPP and how these changes influenced their understanding of HI. Conclusion The results challenge the idea that HL and eHL are fixed, stable, personal characteristics. On the contrary, HL/eHL, in this case particularly the understanding of HI, depends on the individual (temporary) physical and cognitive capacity of the patient and adaptation in the institutional and private contexts.