Hazardous drugs (HD), which need to be handled with care, may be administered through a feeding tube using the simple suspension method. However, instrument contamination during HD administration with the simple suspension method remains unclear. Therefore, to minimize such contamination during the simple suspension method using an injector, we propose the following exposure countermeasures method: (1) Wear two layers of gloves. (2) Prepare injectors for administration and flushing. (3) Use caps. (4) Replace outer gloves after the removal of tablets from the press-through package (PTP) sheet. (5) Handle drugs on a tray. (6) Inject while wrapping the connection site between the injector for administration and the tube with gauze. (7) Wrap the connection site between the injector and tube with gauze. (8) Do not point the injector downward. To establish whether these countermeasures method are effective, 16 ward nurses who routinely administer drugs via a feeding tube were enrolled as subjects. By visual evaluation, we compared differences in instrument contamination between a suspension using a medicine cup and administration via a feeding tube (the conventional method) and the exposure countermeasures method. Exposure with the countermeasures method under our instruction was markedly lower than that with the conventional method. Furthermore, after implementing the exposure countermeasures method, most nurses noted that caution and awareness of exposure countermeasures increased. Thus, to minimize exposure, we recommend the implementation of the exposure countermeasures method and increasing knowledge and awareness of measures against exposure.