When patients tell clinicians about their symptoms, they relate in particular their chief complaint (CC), the main reason for seeking treatment. In clinical trials on symptomatic disease, researchers a priori select one patient-reported outcome (PRO) as the primary endpoint, though another symptom may be of greater significance and more meaningful to the patient in terms of relief. Previous research has reported the symptoms which patients with pharyngitis complain of.1 To determine which of three most frequent PROs (odynophagia, dysphagia, swollen throat) is “primary” to individual patients and possibly useful in designing and analyzing clinical trials, 369 patients ≥18 years of age with acute sore throat (≤3 days) were evaluated at different clinical sites for physical evidence of pharyngitis on the Tonsillo-Pharyngitis Assessment (TPA) and cultured for bacterial throat infection. They used 100-mm visual analog scales to rate three pharyngeal symptoms: odynophagia on the sore throat pain intensity scale (STPIS); dysphagia on the difficulty swallowing scale (DSS); and sensation of swollen throat on the swollen throat scale (SwoTS).2 All patients had pharyngitis (TPA>4), 10% due to Group A beta-hemolytic Streptococcus. For many patients one symptom (alone or with another symptom) was predominant: for 41% of patients, throat pain was the most severe symptom; for 33% of patients, swollen throat was most severe; for 31% of patients, difficulty swallowing was most severe. As in other medical conditions, we found that patients with pharyngitis have different symptoms of varying severity. Because it is the patient's worst symptom, CC may be more sensitive to drug effects than other endpoints, especially when a lower dose or a range of doses is studied. We propose the CC, a patient-defined endpoint, as an individualized outcome for clinical trials. (1.Schachtel B, Arch Int Med 1991; 2.Schachtel B, Clin Pharmacol Ther 1988.) Supported by a grant from Reckitt Benckiser. When patients tell clinicians about their symptoms, they relate in particular their chief complaint (CC), the main reason for seeking treatment. In clinical trials on symptomatic disease, researchers a priori select one patient-reported outcome (PRO) as the primary endpoint, though another symptom may be of greater significance and more meaningful to the patient in terms of relief. Previous research has reported the symptoms which patients with pharyngitis complain of.1 To determine which of three most frequent PROs (odynophagia, dysphagia, swollen throat) is “primary” to individual patients and possibly useful in designing and analyzing clinical trials, 369 patients ≥18 years of age with acute sore throat (≤3 days) were evaluated at different clinical sites for physical evidence of pharyngitis on the Tonsillo-Pharyngitis Assessment (TPA) and cultured for bacterial throat infection. They used 100-mm visual analog scales to rate three pharyngeal symptoms: odynophagia on the sore throat pain intensity scale (STPIS); dysphagia on the difficulty swallowing scale (DSS); and sensation of swollen throat on the swollen throat scale (SwoTS).2 All patients had pharyngitis (TPA>4), 10% due to Group A beta-hemolytic Streptococcus. For many patients one symptom (alone or with another symptom) was predominant: for 41% of patients, throat pain was the most severe symptom; for 33% of patients, swollen throat was most severe; for 31% of patients, difficulty swallowing was most severe. As in other medical conditions, we found that patients with pharyngitis have different symptoms of varying severity. Because it is the patient's worst symptom, CC may be more sensitive to drug effects than other endpoints, especially when a lower dose or a range of doses is studied. We propose the CC, a patient-defined endpoint, as an individualized outcome for clinical trials. (1.Schachtel B, Arch Int Med 1991; 2.Schachtel B, Clin Pharmacol Ther 1988.) Supported by a grant from Reckitt Benckiser.