There has been very limited research done on fragrance chemicals. The Research Institute For Fragrance Materials has done some testing. The RIFM has published monographs on about 1200 fragrance chemicals. This testing is mainly dermatalogical. Since many fragrance chemicals are used also in flavors there has been some testing done on how some substances are metabolized and acute toxicity.

There has been little to no testing on the respiratory effects of fragrance materials despite the fact that virtually all the chemicals are volatile organic compounds and respiratory exposure is significant. And although some fragrance chemicals are known to be neurotoxic such as musk amberette and AETT neurological testing has not been done on most fragrance chemicals.

Due to copyright considerations of using the abstracts for the articles only a brief description of the articles are provided. The description is linked to information available on

  • Musk Xylene, a common synthetic fragrance chemical is found in blood samples from the general population.
  • Coumarin, which has been banned for use in foods because of reports of hepatotoxicity in rodents is still a commonly used fragrance chemical. This study shows there is systemic absorption of coumarin through the skin.
  • d-Limonene when oxidized forms strong contact allergens. This study investigates the occurance of contact allergy to oxidized limonene in the air.
  • 1-8-cineol is absorbed from the air and is dected in the blood.
  • Perfume factory was one of the environmental factors connected with higher localized prevalence of asthma
  • Benzyl acetate may be absorbed systemically through the skin in humans, but absorption is greater in rats than in humans.
  • Blood flow in the brain is effected by inhaling fragrance chemicals.
  • Citral has marked vasoactive effects in rats
  • EEG/ERP experiments show low level and undetected odors can effect neurophysiology
  • Motility in mice is significantly decreased after inhalation of fragrance chemicals.
  • Cinnamaldehyde acts as a haptan and binds with protein to cause allergic reactions 
  • "Fragrance Free" products may contain fragrance chemicals and cause problems for those with fragrance allergies
  • "Natural" cosmetics may contain synthetic ingredients

  Recent studies indicate the nose and the olfactory system are direct pathways to the brain. The blood / brain barrier that helps protect the brain from substances in the blood stream does not necessarily protect the brain from substances that are inhaled.  

Gianutsos G, et al.
Accumulation of manganese in rat brain following intranasal
Fundam Appl Toxicol. 1997 Jun; 37(2): 102-105.

Hastings L, et al.
Olfactory primary neurons as a route of entry for toxic agents
into the CNS.
Neurotoxicology. 1991; 12(4): 707-714.

Evans JE, et al.
Behavioral, histological, and neurochemical effects of nickel
(II) on the rat olfactory system.
Toxicol Appl Pharmacol. 1995 Feb; 130(2): 209-220.

Thorne RG, et al.
Quantitative analysis of the olfactory pathway for drug delivery
to the brain.
Brain Res. 1995 Sep 18; 692(1-2): 278-282.

Tjalve H, et al.
Uptake of manganese and cadmium from the nasal mucosa into the
central nervous system via olfactory pathways in rats.
Pharmacol Toxicol. 1996 Dec; 79(6): 347-356.

Ghantous H, et al.
Accumulation and turnover of metabolites of toluene and xylene in nasal mucosa and olfactory bulb in the mouse.
Pharmacol Toxicol. 1990 Feb; 66(2): 87-92.


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