Many essential oils can be used internally. When they are ingested it should be very light in the order of just a drop per serving. Some oils are edible or used as spices but are not suitable for ingestion as aan essential oil. Here’s a list of 20 essential oils that are generally not recommended for ingestion:

- Arborvitae Oil
- Birch Oil
- Calamus Oil
- Camphor Oil
- Cassia Oil
- Cedarwood Oil (Virginian)
- Cypress Oil
- Dill Oil
- Eucalyptus Oil (Eucalyptus globulus)
- Fennel Oil (Bitter)
- Horseradish Oil
- Hyssop Oil
- Mugwort Oil
- Mustard Oil
- Oregano Oil
- Pennyroyal Oil
- Pine Oil (Scots Pine)
- Rue Oil
- Savory Oil
- Wintergreen Oil
Please note that this list is not exhaustive, and there may be other essential oils that should also be avoided for internal use. It is essential to consult with a qualified aromatherapist, herbalist, or healthcare professional for guidance before considering ingesting any essential oils. They can provide you with tailored advice based on your specific needs and health conditions.