OBJECTIVES: Effective communication of risk of medication side effects is necessary in order to minimize its misinterpretation and over-estimation by patients. The study evaluated effect of communication style (verbal vs verbal + numeric) on perception of risk of experiencing medication side effects of different frequency and severity levels. METHODS: Participants were randomly presented with information on medication side effects using either verbal (e.g. ‘rarely’) or verbal + numeric (e.g. ‘rarely i.e. 2 out of 100’) communication style for frequency descriptions, in a 2 (communication style: verbal, verbal combined with numeric frequency) X 2 (side effect frequency: low, high) X 2 (side effect severity: mild, severe) experimental design. Perception of risk of experiencing side effects was measured and test for analysis of variance was performed. RESULTS: Communication style was observed to significantly affect risk perception for certain combinations of severity and frequency. It was observed that with combined communication style (verbal + numeric), risk perception of severe side effects of low frequency decreased (mean difference: 11.24; C.L.: 4.60 – 17.82) whereas that of mild side effects of high frequency side increased (mean difference: 7.80; C.L.: 1.21 – 14.39) as compared to only verbal communication style. It was also observed that the low and high frequency side effects were better distinguished with respect to their risk when combined communication style was used (mean risk perception difference between low and high frequency side effects: 36.24; C.L.: 31.58 – 40.89) as compared to verbal only (mean difference: 22.2; C.L.: 17.53 – 26.84). Significant main effects of frequency and severity on risk perception were also observed. CONCLUSIONS: Use of numeric frequencies along with verbal descriptions of risk of medication side effect helps in better understanding of underlying risk and reduces its over-estimation, especially for low frequency side effects. Healthcare professionals should take into consideration these effects while communicating side-effect risks to their patients.