1 month. According to relevant data, lavender essential oil can relieve insomnia caused by stress. When sleeping, drop 1-2 drops of lavender essential oil on the pillow or 2 drops of lavender essential oil on the cotton ball and put it in the pillow. In the long run, it can be used for a month. Soaking feet with hot water in cold weather helps blood circulation, relaxes local muscles and nerves, and effectively helps sleep. The best duration is 10- 15 minutes, and the water depth is above the ankle 10cm. Dilute 2-4 drops of lavender essential oil with milk and soak your feet with hot water to prevent beriberi.