Introduction C-reactive protein (CRP) is a widely used laboratory test for assessing infections, inflammatory diseases, and malignancies, playing a critical role in clinical diagnosis and management. Despite its utility, CRP measurement practices vary among physicians, often influenced by training and clinical experience. This study explores general physicians' perceptions of CRP measurement in clinical practice, focusing on its diagnostic value, associated dilemmas, and impact on clinical growth and decision-making. Methods This qualitative study employed thematic analysis to examine the perceptions of general physicians at Unnan City Hospital, Unnan, Japan regarding CRP measurement. Sixteen general physicians were selected through purposive sampling and participated in one-on-one semi-structured interviews. The interviews were conducted in Japanese, recorded, transcribed verbatim, and analyzed inductively to identify themes. The analysis involved iterative coding and extensive discussion among the research team to ensure the reliability and validity of the findings. Results Three main themes emerged from the analysis: the usefulness of CRP for diagnosis and collaboration, dilemmas associated with CRP usage, and clinical growth through reconsideration of CRP's importance. Physicians highlighted CRP's value in distinguishing inflammatory from non-inflammatory diseases, predicting clinical courses, and facilitating communication with specialists. However, dilemmas arose from discrepancies between CRP levels and clinical symptoms, the influence of various non-specific factors, and habitual testing driven by training, leading to unnecessary tests and diminished clinical skills. Participants recognized the need to view CRP as one of many diagnostic tools, cultivate a habit of questioning its necessity, and reflect on its use to enhance clinical reasoning and professional growth. Conclusions CRP measurement is a valuable diagnostic tool, but effective use requires a balanced and critical approach. Discrepancies between CRP levels and clinical symptoms can lead to over-reliance on laboratory results and unnecessary testing. General physicians should integrate CRP within a broader diagnostic framework, combining it with patient history, physical examination, and other tests. Reflecting on the necessity and implications of CRP measurements can improve clinical reasoning and decision-making, ultimately enhancing patient care and resource management. Future research should explore similar perceptions in diverse healthcare settings and develop strategies to optimize CRP use in clinical practice.