The popularity of complementary and alternative medicine (CAM) has increased Trusted Source over the past few decades, and essential oils are a part of that. But what exactly are essential oils? For those new to this trend, these incredibly potent oils some of which have been around for centuries are extracted from plants to capture their flavors, scents, and overall beneficial properties When applying oils topically, always use a carrier oil These are oils used to dilute essential oils, like coconut or jojoba oil.