The most important initial step in taking a patient's history is eliciting the chief complaint in the patient’s own words. This step focuses the clinical encounter on the primary reason for the visit, guiding further questioning and examination. It ensures that the clinician understands the patient’s perspective and concerns directly, which is essential for accurate diagnosis and patient-centered care. Without this, subsequent history components may lack context and relevance, potentially missing key clinical information. Eliciting the chief complaint sets the foundation for an efficient and effective clinical evaluation.

Reference: Bates' Guide to Physical Examination and History Taking, Lynn Bickley, 13th Edition.