The Complete Guide to Aromatherapy suggests the following: one drop of lavender oil, two drops of rosemary, one drop of peppermint, and three drops of thyme in a warm bath. Lavender cleanses, peppermint rejuvenates and stimulates, rosemary cleanses the liver and helps ease nerves, and thyme treats mental fatigue as well as a number of other problems. Do not use rosemary or thyme, however, if you are pregnant because each can act as an abortive agent.
— Robin Hereens Lysne in Sacred Living