Citronellol (Dihydrogeraniol, (±)-β-Citronellol), a constituent of rose and geranium oils, is used in perfumes and insect repellents. Citronellol can cause necrotic apoptosis of NCI-H1299 cells by up-regulating TNF-α, RIP1 / RIP3 activities, and down-regulating caspase-3 / caspase-8 activities. Citronellol also results in a biphasic increase in ROS production at 1 h and at 12 h in NCI-H1299 cells.