Objective Chemotherapy is widely prescribed for lung cancer with palliation as primary end point. This study aimed at determining how preconceptions about lung cancer and its treatment interact with medical discourse into acceptance of chemotherapy. Methods Twenty‐three purposively selected patients who recently accepted chemotherapy were invited to participate in this survey consisting of semi‐structured in‐depth interviews. Grounded theory was applied to investigate participants' perceptions of the context that have surrounded their decision to undergo chemotherapy. Results Major drivers of social representation of illness were linked with stigma. Participants also evoked the disease itself as a stereotype representation of incurable disease. Significant others' experiences were major components of participants' knowledge of chemotherapy. Searching for information regarding lung cancer actively confronted participants with the disease and its prognosis. However, the searching process was self‐limited because of the poor prognosis of the disease, insofar as complete information would have precluded from any hope. We therefore identified 3 domains that provide insights into the participant's views and attitude toward chemotherapy: (i) synthesizing preconceptions of disease and chemotherapy with personal medical case; (ii) slowly constructing complex knowledge of cancer and treatment; and (iii) accepting chemotherapy as a surrogate for acknowledging incurable disease. Conclusion Patients have preconceptions about chemotherapy that result from complex features involving social perception, stigma, and significant others' experiences. In this context, developing a personal knowledge about lung cancer and its treatment is a slow construction. This process needs time to be explained and reformulated, so that patients might give their informed consent.