Natural and artificial radionuclide concentrations were determined and evaluated in 12 different medicinal plants used in Rize Province of Turkey. The levels of Ra-226, Th-232, K-40 and Cs-137 were specified in medicinal plants and a germanium detector with high-purity was used for these measurements. Mean activity values of Ra-226, Th-232, K-40 and Cs-137 in medicinal plants were obtained to be 4.48, 1.83, 259.2 and 0.70 Bq kg(-1), respectively. The obtained values were compared with the values reached in similar studies conducted in different countries. All activity values of Ra-226, Th-232 and K-40 determined in the present study were found to be lower than the worldwide mean values. In addition, the following radiological parameters were determined in medicinal plants and compared with the recommended limits: radium equivalent activity (Ra-eq), annual gonadal dose equivalent (AGDE), absorbed gamma dose rate (D), exposure rate (ER), gamma representative level index (RLI), annual effective dose (AED), and excess lifetime cancer risk (ELCR). Pearson correlation coefficients were determined to assess the correlations between radioactive variables in medicinal plants. The radiological values determined in this study are within the recommended safety limit and the medicinal plants do not pose any significant radiological risk to human health.