The oils listed below present risks of toxicity or of skin irritation, etc. and should not be used in aromatherapy. However, we have listed some of them in this databse.

ALMOND (BITTER) (Containing Prussic Acid)
BOLDO LEAF CALAMUS
CAMPHOR (BROWN)
CAMPHOR (YELLOW)
CASSIA
CINNAMON BARK
CLOVE BUD
CLOVE LEAF
CLOVE STEM
COSTUS
DWARF PINE
ELECAMPANE FENNEL (BITTER)
HORSERADISH
JABORANDI LEAF
MUGWORT (ARMOISE)
MUSTARD
ORIGANUM
ORIGANUM (SPANISH)
PENNYROYAL (EUROPEAN)
PENNYROYAL (N. AMERICAN)
RUE
SASSAFRAS
SASSAFRAS (BRAZILIAN)
SAVIN SAVORY (SUMMER) SAVORY (WINTER)
SOUTHERNWOOD
TANSY
THUJA (CEDARLEAF)
THUJA PLICATA
WINTERGREEN
WORMSEED
WORMWOOD

In addition, there are some oils which have valuable therapeutic properties but which need to be used carefully with an understanding of possible undesirable effects. With the exception of BERGAMOT which is prefectly safe in use as long as exposure to strong sunlight is avoided, it may be wiser for the general reader to avoid these oils, leaving them to the trained therapist.

POSSIBLY TOXIC OILS

SAGE - Salvia officinalis
ANISEED - Pimpinella anisum

There are many well-substantiated reports of side-effects from the use of Sage oil. Aniseed presents risks of damage to the nervous system if used for any length of time. you should add these two to the list of oils not to be used at all.

HYSSOP - Hyssopus officinalis

There are some doubts about the safety of Hyssop, so it is best left alone.