Depending on your current health status, there are some essential oils that you should always avoid.
If you are pregnant, stay away from bitter almond, basil, clary sage, clove bud, hyssop, sweet fennel, juniper berry, marjoram, myrrh, peppermint, rose, oregano, coriander, jasmine, cedar wood, rosemary, sage, thyme, and wintergreen oils.
People with hypoglycemia should avoid geranium oil, and those with kidney problems should use juniper, sandalwood, and coriander with caution. If you have epilepsy or any other seizure disorder, do not use hyssop, camphor, sweet fennel, sage, or rosemary oils. People with high blood pressure should never use hyssop, rosemary, sage, and thyme oils.