Many natural components of plants extract are studied for their beneficial effects on health and particularly on carcinogenesis chemoprevention. In this study, we investigated the effect of citral (3,7-dimethyl-2,6-octadienal), a key component of essential oils extracted from several herbal plants, on the proliferation rate, cell cycle distribution, and apoptosis of the human breast cancer cell line MCF-7. The effects of this compound were also tested on cyclo-oxygenase activity. Citral treatment caused inhibition of MCF-7 cell growth (IC50-48 h: 18 × 10−5 m), with a cycle arrest in G2/M phase and apoptosis induction. Moreover, we observed a decrease in prostaglandin E2 synthesis 48 h after citral treatment. These findings suggest that citral has a potential chemopreventive effect.