To estimate the exposure of pharmacists to drugs during tablet crushing, we collected room dust in four pharmacies and a hospital and analyzed the concentrations of the drug ingredient. The ingredient concentrations in the room dust were detected in the range of 15–18000 µg/m³, and the median concentration was 320 µg/m³. The amount of exposure to pharmacists was estimated between 0.8–960 µg/crush, with a median of 17 µg/crush, when the respiratory volume of the pharmacist was 8 L/min. These maximum and median values were more than 10 times higher than those during the previously reported powder preparations, demonstrating that the working environment for pharmacists who crushed tablets posed more health hazards. As countermeasures, working on a bench with dust remover reduced the exposure by 99.0% compared to that on a normal bench, and wearing a medical mask reduced the exposure by 97%. The combined reduction rate of both measures was calculated to be over 99.9%. Moreover, we compared the estimated exposure by the crusher with the rotatory blade and that with two rotatory mortars and found that the estimated exposure using the latter was much less (lower than 1/1000) than that with the former. Thus, the above measures can be used to reduce the exposure of pharmacists to drugs during tablet crushing.