Certain plant-derived essential oils are classified as ‘minimum risk' pesticides that require no registration with the Environmental Protection Agency and, therefore, have become attractive in formulations of pest-control products. In Petri dish assays, fumigation of a pyrethroid-susceptible strain of bed bugs, Cimex lectularius L. (Hemiptera: Cimicidae), with various essential oils results in mortality that approaches or equals 100% after 5 d. However, when bed bugs were exposed to the same essential oils in sealed, commercial trash bags for 5 d, only rosemary oil killed greater than 99% of the bed bugs. These results are compared with a commercial product that contains cold-pressed neem oil that killed 100% of the exposed bed bugs in both the Petri dish and trash bag studies.