In the present work, Thoron (220Rn) concentrations was determined for (44) samples of medical drugs derived from medicinal plants in Iraqi pharmacies. Solid state nuclear detectors (SSNTDs) CR-39 detectors were used in the present study. The results show that the Thoron concentrations in the samples under study ranged from 1.82 Bq/m3 to 66.48Bq/m3, with an average 32.91±3.36 Bq/m3. All results of radon concentrations for all samples were much less than the acceptable lower limits of the action level, by International Commission on Radiological Protection (ICRP). So, the intake of the studied samples of medical drugs in Iraq does due to 220Rn not lead to substantial changes in the internal effective dose. It is conclude that the thoron concentrations in the samples under study were not significant from a health hazard point of view.