Cannabidiol, or CBD, is a compound in marijuana and hemp plants. It doesn’t get you high, but it can help you nod off. CBD oil may work by taking the edge off. One study found that people who took it felt less anxious and slept better within a month. CBD may make some people tired or want to throw up. Experts are still looking at how much is needed, but research suggests a dose of 25-175 milligrams a day.