TOXIC - They are either extremely toxic or cause severe skin irritation even in a diluted state. Use at your own risk: Bitter Almond, Arnica, Boldo, Broom, Buchu, Calamus, Camphor, Cassia, Chervil, Cinnamon, Costus, Deertongue, Elecampane, Fennel, Horseradish, Jaborandi, Melilotus, Mugwort, Mustard, Oregano, Pennyroyal, Pine, Rue, Sage(common), Santolina, Sassafras, Savine, Savory, Tansy, Thuja, Thyme, Tonka, Wintergreen, Wormseed and Wormwood.
USED IN SMALL DOSES FOR NO LONGER THAN 2 WEEKS - Fairly toxic or may have side effects such as nausea, vomiting and headaches and should be used with extreme caution: Ajowan, Anise star, Aniseed, Basil, Bay laurel, Bay, Calamintha, Camphor, Cascarrilla bark, Cassie, Cedarwood, Cinnamon, Clove, Coriander, Eucalyptus, Fennel, Hops, Hyssop, Juniper, Nutmeg, Parsley, Pepper, Pine, Sage, Tagetes, Tarragon, Thyme, Tuberose, Tumeric, Turpentine, and Valerian.
IRRITATE THE SKIN IF USED IN HIGH CONCENTRATION - Use in half the recommended dilution, no more than 3 drops (oils) in a bath: Ajowan, Allspice, Aniseed, Basil, Black pepper, Borneol, Cajeput, Caraway, Cedarwood, Cinnamon, Clove, Cornmint, Eucalyptus, Garlic, Ginger, Lemon, Parsley, Peppermint, Pine, Thyme, and Tumeric.
IRRITATION ON SENSITIVE SKIN - May cause eczema or dermatitis with people who have very sensitive skin. (Always test on the back of your wrist, and leave for an hour to 24 hours. If irritation occurs bathe area with cold water and try a weaker concentration.): Aniseed, Basil, Bay Laurel, Benzoin, Bergamot, Cade, Cajeput, Cananga, Cedarwood, Chamomile, Citronella, Garlic, Geranium, Ginger, Hops, Jasmine, Lemon, Lemongrass, Lemon Balm, Litsea cubeba, Loveage, Mastic, Mint, Orange, Peru balsam, Pine, Styrax, Tea tree, Thyme, Tolu balsam, Tumeric, Turpentine, Valerian, Vanilla, Verbena, Violet, Yarrow, and Ylang Ylang.
PHOTOTOXIC - Can cause the skin to darken if exposed to direct sunlight. Do not use at all if the area will be exposed to sunlight: Angelica Root, Bergamot, Cumin, Ginger, Lemon, Lime, Loveage, Mandarin, Orange, and Verbena.
AVOID DURING PREGNANCY - Due to the effects on the reproductive organs, and the sensitivity of the fetus: Ajowan, Anjelica, Anise star, Aniseed, Basil, Bay Laurel, Calamintha, Cedarwood, Celery Seed, Cinnamon, Citronella, Clary sage, Clove, Cumin, Cypress, Fennel, Hyssop, Jasmine, Juniper, Labdanum, Lovage, Marjoram, Myrrh, Nutmeg, Parsley, Pennyroyal, Peppermint, Rose, Rosemary, Snakeroot, Sage, Tarragon, and Thyme.
AVOID WITH HIGH BLOOD PRESSURE - Black pepper, Hyssop, Lemon, Lemongrass, Nutmeg, Rosemary, Sage, and Thyme.
AVOID WITH LOW BLOOD PRESSURE - Chamomile, Lemon Balm, Lavender, Marjoram, and Ylang Ylang.
AVOID WITH DIABETES - Angelica
AVOID WITH KIDNEY PROBLEMS - Juniper
AVOID WITH HOMEOPATHIC TREATMENTS - Black pepper, Camphor, Eucalyptus, and Peppermint.
AVOID WITH ALCOHOL CONSUMPTION - will increase the effects of alcohol: Aniseed, Clary Sage, and Fennel.
AVOID WITH DEPRESSION - Basil
AVOID WITH EPILEPSY - Fennel, Hyssop, Sage and Rosemary.