Turner RB, Fowler SL, Berg K. Treatment of the common cold with troxerutin. APMIS 2004;112:605–11. The rutosides are naturally occurring flavonoids that have documented effects on capillary permeability and edema. The purpose of this study was to assess the effect of troxerutin, one of the rutosides, on the symptoms of the common cold. Ninety-four volunteers with common cold symptoms were recruited for participation in the study. Volunteers were randomized to either active treatment (n=49) with troxerutin (50 mg) and Zn gluconate (25 mg) or control treatment (n=45) with 10 mg Zn gluconate. Symptoms were assessed by subjective symptom score prior to treatment and then daily for the next 4 days. The total symptom score over the 4 days of study treatment was 27.7±2.0 (mean±SEM) and 33.0±2.6 in the active and control groups, respectively (p=0.10, unpaired t-test). The total daily symptom score on day 1 was reduced by 11% compared to baseline in the active group and by 1% in the control group (p=0.03). Evaluation of the effect of treatment on individual symptoms revealed a significant effect on rhinorrhea. The total rhinorrhea score over the course of the study was 3.7±0.4 in the active group compared to 5.1±0.5 in the control group (p=0.025, unpaired t-test). Daily rhinorrhea scores were significantly lower in the active group on study days 1 and 3. Based on this preliminary study, the possibility that the rutosides might provide a safe and effective treatment for rhinorrhea in the common cold deserves systematic evaluation.