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General Description

Synonyms: caprylic acid; n-caprylic acid; C8 acid; 1-heptanecarboxylic acid; light cut fatty acids; n-octoic acid; n-octanic acid; n-octylic acid; Neofat 8

OSHA IMIS Code Number: C725

Chemical Abstracts Service (CAS) Registry Number: 124-07-2

NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: RH0175000

Department of Transportation Regulation Number (49 CFR 172.101) and Guide: 3265 153

Chemical Description and Physical Properties:

clear viscous very faintly yellow liquid
molecular weight: 144.24
vapor pressure: 1 mmHg @ 78°C
molecular formula: C8H16O2
boiling point: 237-238°C
melting point: 16.5°C
flash point: 110°C closed cup

Health Factors

Potential Symptoms: Irritation of eyes, skin, throat; skin redness, pain, burns, blisters (from contact with liquid); cough, shortness of breath (when vaporized by heating); eye redness, pain, burns, loss of vision (from liquid); INGES. ACUTE: Burning sensation, abdominal pain.

Health Effects: Irritation-Eyes, Nose, Throat, Skin---Marked (HE14)

Affected Organs: Eyes, skin, respiratory system


  1. OSHA does not have a PEL for octanoic acid.
  2. Octanoic (caprylic) acid is listed by the FDA as a direct food substance affirmed as generally recognized as safe (GRAS) when used in foods at concentrations ranging from 0.001 to 0.04% (depending upon the food) according to good manufacturing practice (21 CFR 184.1025).
  3. Octanoic acid is a medium-chain fatty acid that constitutes as much as 13% of the free fatty acid pool in healthy humans.
  4. A low potential of octanoic acid to induce developmental toxicity in rats when compared with other 8-carbon fatty acids (e.g., valproic acid) was attributed, in part, to pharmacokinetic characteristics that limited fetal exposure to it after oral administration to pregnant rats.
  5. The intraperitoneal injection of mice with an octanoic acid dose of 15 µmol/g (43-48 mg/mouse) was reported to cause coma after a 3-4 minute period of drowsiness.
  6. Studies in rats indicate that octanoic acid is a significant source of oxidative energy in the brain. It has been suggested that impaired oxidation of medium-chain fatty acids like octanoic acid may contribute to neurotoxicity in the Reye syndrome.
  7. [13C]-labeled octanoic acid is used in a non-invasive method to measure gastric emptying time of a meal with a breath-testing protocol.

Literature Basis:

  • Ebert, D., Haller, R.G. and Walton, M.E.: Energy contribution of octanoate to intact rat brain metabolism measured by 13C nuclear magnetic resonance spectroscopy. J. Neurosci. 23(13): 5928-5935, 2003.
  • Hellmig, S., et al.: Gastric emptying time of fluids and solids in health subjects determined by 13C breath tests: influence of age, sex and body mass index. J. Gastroenterol. Hepatol. 21(12): 1832-1838, 2006.
  • McCandless, D.W.: Octanoic acid-induced coma and reticular formation energy metabolism. Brain Res. 335(1): 131-137, 1985.
  • Scott, W.J., Jr., Collins, M.D. and Nau, H.: Pharmacokinetic determinants of embryotoxicity in rats associated with organic acids. Environ. Health Perspect. 102(Suppl. 11): 97-101, 1994.
  • Yoshida, Y., Singh, I., Singh, A.K., Tecklenberg, F.W., Brown, F.R., 3rd and Darby, C.P.: Reye syndrome: rate of oxidation of fatty acids in leukocytes and serum levels of lipid peroxides. J. Exp. Pathol. 4(3): 133-139, 1989.

Date Last Revised: 05/30/2007

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