Aromatherapy is the therapeutic use of essential oil from herbs, flowers, and other plants. The aim of this overview was to provide an overview of systematic reviews evaluating the effectiveness of aromatherapy. We searched 12 electronic databases and our departmental files without restrictions of time or language. The methodological quality of all systematic reviews was evaluated independently by two authors. Of 201 potentially relevant publications, 10 met our inclusion criteria. Most of the systematic reviews were of poor methodological quality. The clinical subject areas were hypertension, depression, anxiety, pain relief, and dementia. For none of the conditions was the evidence convincing. Several SRs of aromatherapy have recently been published. Due to a number of caveats, the evidence is not sufficiently convincing that aromatherapy is an effective therapy for any condition.