Some sources recommend against the use of parsley essential oil (Petroselinum crispum or Petroselinum sativum) because it contains apiole, which is potentially toxic.
However, the apiole content of parsley seed essential oil (the most commonly available oil, though a parsley leaf oil is also produced) can vary from 11.3–67.5%. If you choose to use the seed oil, use it cautiously.
Parsley leaf oil contains less apiole and may be safer, but I didn't find much reliable information on this oil.
Plant family: Apiaceae
Production: Steam distilled from the seeds (or the leaves for parsley leaf).
Aroma: Herbaceous, green and slightly woody.
Perfume/Aromatic note: Middle. The seed oil is used in perfumes, especially colognes for men and mixes well with spicy essential oils.
Is parsley safe to use during pregnancy? No, and do not use during breastfeeding.
Is parsley essential oil safe for children? Do not use with young children. Consult a professional about use with older children.
Parsley seed oil has three chemotypes, with either parsley apiole, myristicin, or allytetramethoxybenzene as the main constituent. Most commercial oils contain a high percentage of parsley apiole.
Cautions: Do not use the seed oil if you have kidney disease. The seed oil may cause skin irritation and sensitization. Essential Oil Safety recommends a dermal maximum of 1.1% and notes possible drug interaction and a risk of toxicity to the liver and kidneys.
The Encyclopedia of Essential Oils (updated edition): Parsley seed may help relieve arthritis, broken blood vessels, cellulitis, rheumatism, sciatica, flatulence, indigestion, hemorrhoids, missing periods, and menstrual pain.
Essential Oils All Natural Remedies: Use parsley seed at a dilution of less than 1%. The oil may have the following benefits:
Aromatica: A Clinical Guide to Essential Oil Therapeutics, Volume 2, recommends against the use of parsley seed except by professional aromatherapists.
The Complete Guide to Aromatherapy, Third Edition, Vol. 1, recommends against the use of parsley seed but notes the following uses suggested by other sources:
AromaWeb: Parsley seed essential oil has a diuretic effect and may help shrink blood vessels. The oil's aroma adds an herbaceous note to blends. Using this essential oil in the bath creates greater risk of irritation and sensitization—do not add the oil to bath blends.
Jade Bloom: Parsley seed helps remove toxins from the skin and has astringent properties that constrict pores and improve skin complexion. The essential oil may help relieve varicose veins, increase circulation, reduce nausea, calm muscle spasms, and cleanse and disinfect wounds and irritations. The oil also acts as a scalp and hair tonic.
Mixing Essential Oils for Magic: Parsley is a powerful ally for element magic, ritual purification, and general protection. The oil supports balance and concentration, astral work, initiating renewal, and bringing in fresh, new beginnings.