This substance was evaluated for acceptable daily intake for man
    by the Joint FAO/WHO Expert Committees on Food Additives in 1967, and
    1979 (see Annex I, Refs. 14 and 51). A toxicological monograph was
    issued in 1980 (see Annex I, Ref. 52).

         Additional data have become available and are summarized and
    discussed in the following monograph. The previous monograph has been
    expanded and is reproduced in its entirety below.



    Absorption, metabolism and distribution

         Intraperitoneal injection of a single 450 mg/kg dose of 14C
    methoxy labelled eugenol resulted in rapid distribution to all organs.
    Both ether- and water-soluble materials were recovered from most
    tissues and excretions. Only 0.2-1.0% of the dose was eliminated as
    expired 14CO2 (Weinberg et al., 1972). Over 70% of a lethal dose of
    eugenol was recovered on death, from the urine of rabbits (Schroder &
    Vollmer, 1932).

         Administration of single 200 mg doses to rats led to increased
    urinary output of ethereal glucuronides of 33-35 mg/rat in 12 hours
    compared to a control value of 4 mg/rat. Ester glucuronide values were
    unchanged (Yuasa, 1974).

         Studies carried out in liver microsomal preparations from male
    and female Fischer rats and CD-1 mice showed that formation of eugenol
    2',3-epoxide from eugenol occurred in just detectable amounts (Swanson
    et al., 1981).

         Epoxidization of eugenol by rat liver cell cultures has been
    reported. The dihydrodiol metabolite of eugenol has been isolated from
    liver homogenates and urine of rats pretreated with eugenol. These
    metabolites may arise from the action of epoxide hydrase on the
    eugenol epoxide (Delaforge et al., 1980).

         Incubation of eugenol with rat liver epithelial cells resulted in
    production of 4-(2'-3'-dihydroxy)propyl-2-methoxyphenol (Janiaud,

    Effects on enzymes and other biochemical parameters

         The pharmacological effects of eugenol include the previously
    reviewed inhibition of ß-D-glucosiduronic acid conjugation in rats
    receiving 150 mg/animal (Hartiala et al., 1966).

         Hydroxylating activity of liver homogenate on dimethylaminopyrine
    or hexobarbital was depressed in tissue from mice dosed with 160 mg/kg
    of eugenol and sacrificed after 1 hour (Jaffe et al., 1968).

         Eugenol had no effect on aminopyrine-N-demethylation activity in
    the liver of rats given about 10% of the LD50 3 times daily for 2-3
    days. There was a slight decrease in hexobarbital lateral deflection
    time and in urinary ascorbic acid content (Gruebner, 1972).

         Eugenol was reported to inhibit respiration in vitro in
    mitochondria isolated from the liver of adult male, Charles River
    rats. Concentrations of from 0.11 to 3.50 mM of eugenol were present
    in the suspension medium; inhibition of respiration began at
    concentrations of 0.88 mM (Cotmore et al., 1979).

         At 1 mM concentration, eugenol was reported to cause a 61%
    inhibition of noradrenaline induced oxidative metabolism in isolated
    brown fat cells from adult hamsters (Peterson et al., 1980).

         Intraperitoneal injection of 200 mg/kg eugenol induced
    anaesthesia in male Swiss albino mice; the mean sleeping time in a
    group of 10 dosed animals was 17 minutes. Two of the animals died
    within 24 hours of treatment (Sell & Carlini, 1976). Intraperitoneal
    administration of eugenol is also associated with hypothermia in rats
    and myorelaxtion and anticonvulsant effects in mice (Dallmeier &
    Carlini, 1981).

         Eugenol is used as a dental analgesic (Tyler et al., 1977); the
    compound relieves pain from irritated or diseased tooth pulp, but is
    not a true local anaesthetic (Sticht & Smith, 1971).

         Subcutaneous injection of 50 mg of eugenol daily for 7 days
    (total dose 1365 mg/kg bw) to partially hepatectomized male, Charles
    River rats had no effect on rate of liver regeneration (Gershbein,

         Subcutaneous injection of 0.1 ml of purified eugenol in adult
    Walter Reed white rats caused necrosis and inflammation at the
    injection site (Webb & Bussel, 1981).

         Other effects include:


    Animal       Dose        Route             Effect              Reference

    Dog      ca. 50 mg/kg    i.v.        Choleresis              Chabrol, 1931

    Mice     100-340 mg/kg   i.p.        Reduction in rectal     Caujolle &
                                         temperature             Meynier, 1960
             50 mg/kg        i.p.        Increase in sleeping    Seto & Kemp,
                                         time                    1969
                                         pentobarbital - 131%
                                         ethanol - 120%

    Rat      100 mg/kg       i.p.        No effects on           deMello
                                         spontaneous motor       et al.,
                                         activity                1973
             160 mg/kg       i.p.        Severe depression and
                                         paralysis of hind
             200 mg/kg       i.p.        Catatonia

    Frog     0.1-100%        Direct      Blockage of             Kozam, 1977
                             exposure    transmission of
                             of nerve    evoked impulses
                                         in exposed
                                         sciatic nerve

    Special studies on carcinogenicity

         Groups of about 30 young adult female CD-1 mice were fed 0 or
    0.5% eugenol in the diet for 12 months. Other groups received 0.05%
    phenobarbitol or 0.5% dietary eugenol in addition to 0.05%
    phenobarbitol in the drinking-water. The animals received control
    diets for an additional 6 months following administration of the test
    diets. In the groups given only phenobarbitol, 3/29 mice developed
    liver tumours, while no liver tumours were found in the other 3
    groups. The liver was the only organ examined for the occurrence of
    tumours. A second experiment was conducted in which groups of 40 to 60
    male and 40 to 60 female CD-1 mice were given 0 or 2.5 µmol of eugenol
    twice weekly by gavage starting at 4 days of age and continuing until
    35 days of age. The animals were then maintained without dosing until
    the experiment was terminated at 14 months. No effect of treatment
    upon the incidence of liver tumours was noted in either sex. In a
    third study, groups of 40 to 50 male CD-1 mice were injected i.p. at
    1, 8, 15 and 22 days of age with 0.63, 1.26, 2.52 and 5.04 µmol,

    respectively, of eugenol or eugenol 2',3'-epoxide. As compared to
    concurrent controls receiving the trioctanoin solvent only, neither
    treatment group had an increased incidence of liver tumours (Miller et
    al., 1979).

         The ability of eugenol to promote skin tumours was studied using
    groups of 20 female ICR/HA Swiss. One group was given a single
    cutaneous initiating dose of 7,12-dimethylbenz(a)anthrecene (DMBA) to
    the back. This group and another group not initiated with DMBA
    received 3 times weekly cutaneous applications of 5 mg of eugenol for
    63 weeks. No carcinomas were found in either group and no papillomas
    were found in the animals receiving only eugenol. Three animals
    developed papillomas in the group initiated with DMBA and also treated
    with eugenol. Two papillomas and 1 carcinoma developed in control
    animals initiated with DMBA and then treated 3 times weekly with DMSO,
    the solvent control (Van Duuren et al., 1966). In another study
    carried out in the same laboratory, eugenol was reported to have a
    partial inhibitory action on the carcinogenicity of benzo(a)pyrene
    when the compounds were applied together in a carcinogenic skin
    painting study (Van Duuren & Goldschmidt, 1976).

         In a limited study in mice, eugenol did not potentiate the
    tumorigenic effects of methylcholanthrene (Hitchcock, 1952).

         Groups of 50 male F-344 rats were given 3000 or 6000 ppm (0.3 or
    0.6%) of eugenol in the diet for 103 weeks. The animals were given
    diets without eugenol for an additional week prior to the terminal
    sacrifice. Groups of 50 female F-344 rats were fed diets containing
    6000 or 12 500 ppm (0.6 or 1.25%) of eugenol in the diet for 103
    weeks. The animals were given diets without eugenol for an additional
    1 or 2 weeks prior to the terminal sacrifice. Concurrent control
    groups of 40 males and 40 females were maintained on diets without
    eugenol for 105 weeks. There appeared to be a dose-related effect on
    weight gain, especially in the females. Small decreases in feed
    consumption were also noted in the dosed animals. There was no
    significant compound-related effect on survival. Endometrial stromal
    polyps of the uterus were found in increased incidence in female rats.
    The incidence was 6/40, 6/50 and 16/50 in the controls, low and high
    doses, respectively. Incidence of alveolar-bronchiolar adenomas of the
    lung in males was 0/40, 5/49 and 2/50 in the controls, low dose and
    high dose, respectively. The historical incidence of this tumour in
    male F-344 control rats at the performing laboratory is 6/299 (2%). No
    statistically significant increase in this tumour was observed in high
    dose males or in any of the female groups. C-cell adenomas of the
    thyroid gland were observed at the following incidence in females:
    3/40, 11/49 and 2/50 in the controls, low dose and controls,
    respectively. The increase was statistically significant in the low
    dose animals. There was no increased incidence of this tumour at
    either dose in the males. The conclusion of the report stated that
    eugenol was not carcinogenic to rats (NTP, 1980).

         Groups of 50 male and 50 female B6C3F1 mice were given 0, 3000 or
    6000 ppm (0, 0.3 or 0.6%) of eugenol in the diet for 103 weeks.
    Animals were maintained on a control diet for another 2 weeks prior to
    terminal sacrifice. A small dose-related decrease in weight gain was
    noted for both males and females throughout the study. No compound-
    related clinical signs were reported; however, survival was somewhat
    lower in high dose males and low dose females but the effect was not
    statistically significant. The incidence of hepatocellular tumours
    (carcinoma, adenoma) was 14/50, 39/45 and 19/49 in the controls, low
    dose and high dose males. The corresponding incidence in females was
    2/50, 7/49 and 9/49. In the males, the low dose, but not the high
    dose, had a statistically significant increase in hepatocellular
    tumours. The conclusion of the report stated that there was evidence
    that eugenol increased liver tumours in B6C3F1 mice; however, the
    results were judged to be equivocal because of the limited weight of
    this evidence (NTP, 1981).

    Special studies on mutagenicity

         Eugenol was negative in a Salmonella assay employing 4 mutant
    strains (TA-1530, TA-1531, TA-1532, TA-1964) both directly and after
    the use of mouse liver postmitochondrial fraction for activation. It
    was also inactive in a host-mediated assay (Green & Savage, 1978).

         Eugenol was also reported not to be mutagenic in Salmonella
    TA-100 in a liquid suspension assay with or without an S-9 fraction
    from Aroclor induced rat liver (Eder et al., 1980). Negative results
    were also reported with eugenol using Salmonella strains TA-98,
    TA-1535 and TA-100 in the plate assay system with or without liver
    activation from Aroclor or 3-methyl cholanthrene induced rats. The
    2',3'-epoxide of eugenol was mutagenic for strain TA-1535 in the
    absence of a liver activation system (Swanson et al., 1979).

         Eugenol was reported not to be mutagenic to Salmonella strains
    1535, 1537 or 1538 with or without a rat liver activation system. The
    2',3'-epoxy derivative of eugenol was mutagenic to strain TA-1535 with
    or without liver activation (Delaforge, 1977).

         The acute toxic effects include desquamation of the gastric
    mucosa (Hitchcock, 1952), and punctate haemorrhages in dogs (Hartiala
    et al., 1966), gastric inflammation and depression of secretory
    capacity (Sober, 1950), liver discoloration and mottling in rats
    (Taylor et al., 1964) liver congestion in dogs (Lauber & Hollander,

    Acute toxicity

      Animal       Route    (mg/kg bw)       Reference

    Mouse          Oral        3 000     Jenner et al., 1964
                   i.p.          500     Caujolle & Meynier, 1960
                   i.p.          630     Fujii et al., 1970

    Rat            Oral        1 930     Sober et al., 1950
                   Oral        2 680     Taylor et al., 1964

    Guinea-pig     Oral        2 130     Jenner et al., 1964

    Subchronic studies

         Ten male and 10 female rats given 89.7 mg/kg eugenol for 12 weeks
    showed no adverse effects (Trubek Laboratories, 1958).

         Twenty male rats were given increasing doses from 1400 to
    4000 mg/kg bw for 34 days. There was considerable mortality, slight
    liver enlargement and adrenal enlargement. Histology showed enlarged
    liver cells. The forestomach showed moderately severe hyperplasia and
    hyperkeratosis of the stratified squamous epithelium with focal
    ulceration (Hagan et al., 1965).

         In another study, groups of 10 males and 10 females were fed
    diets containing 0, 0.1 and 1.0% eugenol for 19 weeks without any
    adverse effect on growth rate, haematology, organ weights and
    histology of major tissues (Hagan et al., 1967).

         Groups of 5 male and 5 female F-344 rats were fed 6000, 12 500,
    25 000, 50 000 or 100 000 ppm (0.6, 1.25, 2.5, 5 or 10%) of eugenol in
    the diet for 14 days. There were no concurrent controls. One high dose
    male and all high dose females died during the study. There appeared
    to be a dose-related reduction in weight gain (NTP, 1981).

         Groups of 10 male and 10 female F-344 rats received 0, 800, 1500,
    3000, 6000 or 12 500 ppm (0, 0.08, 0.15, 0.3, 0.6 or 1.25%) of eugenol
    in the diet for 90 days. There was no compound-related effect reported
    on mortality or gross or microscopic pathology. Relative to controls,
    weight gain was reduced 12% in the high dose males (NTP, 1981).

         Groups of 5 female and 5 male B6C3F1 mice were given 6000,
    12 500, 25 000, 50 000 or 100 000 ppm (0.6, 1.25, 2.5, 5, or 10%) of
    eugenol in the diet for 14 days. There were no concurrent controls.
    There was a dose-related decrease in weight gain in both males and

    females. All 5 of the males in the 100 000 ppm (10%) group died before
    the end of the study. In the females, all of the 100 000 ppm (10%)
    group died before the end of the study (NTP, 1981).

         Groups of 10 male and 10 female B6C3F1 mice were given 0, 400,
    800, 1500, 3000 or 6000 ppm (0, 0.04, 0.08, 0.15, 0.3 or 0.6%) of
    eugenol in the diet for 13 weeks. There was no mortality, compound-
    related gross or microscopic pathology (NTP, 1981).


         Acutely, high doses of eugenol are hepatoxic to dogs and rats.
    Metabolic data is limited. Formation of small amounts of eugenol
    2',3-epoxide from eugenol using in vitro systems has been reported.
    Mutagenicity tests using Salmonella strains with and without
    activation gave negative results for eugenol, although the
    2',3-epoxide compound was active in these systems. Eugenol was not
    carcinogenic in lifetime study in the rat. In a lifetime study with
    B6C3F1 mice, there was evidence of an increased incidence of liver
    tumours. Statistical analysis of the results suggested a positive
    trend in male mice. Although the incidence of tumours in the female
    mice was increased at the low dose level, the effect was not dose
    related. The significance of this result is difficult to interpret and
    has been judged to be equivocal. In this respect, it is important to
    note that in studies in CDI mice which compared the carcinogenic
    potential of eugenol with that of structurally-related compounds,
    namely estrogal and suffrole, eugenol was negative, whereas suffrole
    was positive. Thus most of the available evidence indicates that
    eugenol is not carcinogenic.

         No studies on teratology or reproduction are available.

         The lifetime feeding study in the rat provides additional
    information for evaluating an acceptable daily intake for man. This
    data supports converting the previous temporary acceptable daily
    intake to an acceptable daily intake.


    Level causing no toxicological effect

    Rat: 250 mg/kg bw in the diet.

    Estimates of acceptable daily intake for man

    0-2.5 mg/kg bw


    Anon. (1978) Scientific Literature Review of Eugenol and Related
         Substances in Flavor Usage

    Caujolle, F. & Meynier, D. (1960a) Hypothermic activity in the eugenol
         and safrole series, Ann. Pharm. Fr., 18, 601-612

    Chabrol, E. et al. (1931) Cholagog action of guaiacol derivatives,
         C. R. Soc. Biol., 107, 1240-1243

    Cotmore, J. M. & Burke, A. (1979) Respiratory inhibition of isolated
         rat liver mitochondria by eugenol, Arch. Oral Biol., 24,

    Dallmeier, K. & Carlini, E. (1981) Anesthetic hypothermic myorelaxant
         and anticonvulsant effect of synthetic eugenol derivatives and
         natural analogues, Pharmacol., 22, 113-127

    Delaforge, M. et al. (1980) Biotransformation of allylbenzene
         analogues in vivo and in vitro through the expoxide-diol
         pathway, Xenobiotica, 10, 737-747

    Delaforge, M. et al. (1977) Activation métabolique d'un promutagène
         naturel: l'eugénol, par des cultures réplicatives de cellules
         épithéliales de foie de rat adulte, C. R. Soc., 171, 100-107

    De Mello, C. A. et al. (1973) Behavioral observations on compounds
         found in nutmeg, Psychopharmacologia, 31(4), 349-363

    Eder, E. et al. (1980) Mutagenic potential of allyl and allylic
         compounds, Biochem. Pharmacol., 29, 993-998

    Fujii, K. et al. (1970) Structure-activity relations for
         methylenedioxyphenyl and related compounds on hepatic microsomal
         enzyme function, as measured by prolongation of hexobarbital
         narcosis and zoxazolamine paralysis in mice, Toxicol. Appl.
         Pharmacol., 16, 482-494

    Gershbein, L. (1977) Regeneration of rat liver in the presence of
         essential oils and their components, Fd. Cosmet. Toxicol.,
         15, 173-181

    Green, N. R. & Savage, J. R. (1978) Screening of safrole, eugenol,
         their ninhydrin positive metabolites and selected secondary
         amines for potential mutagenicity, Mutation Research, 57,

    Gruebner, I., Klinger, W. & Ankermann, H. (1972) Various substances
         and substance classes with inducer properties. II. Arch. Int.
         Pharmacodyn. Ther., 196(2), 288-297

    Hagan, E. C., Jenner, Paul M., Jones, Wm. I., Fitzhugh, O. Garth,
         Long, Eleanor L., Brouwer, J. G. & Webb, Willis K. (1965) Toxic
         properties of compounds related to safrole, Toxicol. Appl.
         Pharmacol.,, 7(1), 88-24

    Hagan, E. C., Hansen, W. H., Fitzhugh, O. G., Jenner, P. M., Jones &
         Jones, W. I., Taylor, Jean M., Long, Eleanor L., Nelson, A. A.
         Brouwer, J. B. (1967) Food flavorings and compounds of related
         structure. II. Subacute and chronic toxicity, Food Cosmet.
         Toxicol., 5(2), 141-157

    Hartiala, K. J. W., Pulkkinen, M. & Ball, P. (1966) Inhibition of ß-D
         Glucosiduronic acid conjugation (rat and guinea pig) by eugenol,
         Nature, 210(5037), 739-740

    Hitchcock, C. R. (1952) Failure of eugenol and heat to potentiate
         gastric tumor induction by 20-methylcholanthrene in mice,
         J. Natl. Cancer Inst., 12(4), 723-733

    Jaffe, H. et al. (1968) In vivo inhibition of mouse liver microsomal
         hydroxylating systems by methylenedioxyphenyl insecticidal
         synergists and related compounds, Life Sci., 7(9), 1051-1062

    Janiaud, P., Delaforge, M., Levi, Ph., Maume, B. F. & Padieu, P.
         (1976) Etude comparative en culture cellulaire de foie de Rat du
         métabolisme de différents analogues et métabolites d'un
         hépatocancérogène naturel: le safrol, C.R. Soc. Biol.,
         170(5), 1035-1041

    Jenner, P. M. et al. (1964) Food flavorings and compounds of related
         structure. I. Acute oral toxicity, Food Cosmet. Toxicol.,

    Kozam, G. (1977) The effect of eugenol on nerve transmission, Oral
         Surg., 44, 799

    Lauber, F. U. & Hollander, F. (1950) Toxicity of the Mucigogue,
         eugenol, administered by stomach tube to dogs, Gastroenterol.,
         15(3), 481-486

    Miller, J. A., Swanson, A. B. & Miller, E. C. (1979) The metabolic
         activation of safrole and related naturally occurring
         alkenylbenzenes in relation to carcinogenesis by the compound.
         In: Miller, E. C. et al., eds, Naturally occurring
         carcinogens-mutagens and modulators of carcinogenesis, Tokyo,
         Japan Sci. Soc. Press/Baltimore, Univ. Park Press, pp. 111-125

    National Toxicology Program (1981) Carcinogenicity bioassay of
         eugenol. Unpublished. National Toxicology Program, Research
         Triangle Park, pp. 142. Submitted to WHO by the U.S. Food and
         Drug Administration.

    Peterson, B., Curvall, M. & Euzell, C. (1980) Effects of tobacco smoke
         compounds on the noradrenaline induced oxidative metabolism in
         isolated brown fat cells, Toxicology, 18, 1-5

    Schroder, V. & Vollmer, H. (1932) The excretion of thymol, carvacrol,
         eugenol and guaiacol and the distribution of these substances in
         the organism, Arch. Exp. Path. Pharmakol., 168, 331-353

    Sell, A. & Carlini, E. (1976) Anesthetic action of methyleugenol and
         eugenol derivatives, Pharmacology, 14, 367-377

    Seto, T. A. & Keup, W. (1969) Effects of alkylmethoxybenzene and
         alkylmethylenedioxybenzene essential oils on pentobarbital and
         ethanol sleeping time, Arch. Int. Pharmacodyn. Ther., 180(1),

    Sober, H. A., Hollander, F. & Sober, E. K. (1950) Toxicity of eugenol;
         Determination of LD50 on rats, Proc. Soc. Exp. Biol. Med.,
         73(1), 148-151

    Sticht, F. D. & Smith, P. M. (1971) Eugenol; Some pharmacologic
         observations, J. Dent. Res., 50, 1531-1535

    Swanson, A. B., Miller, E. C. & Miller, I. A. (1981) The side-chain
         epoxidation and hydroxylation of the hepatocarcinogens safrole
         and estrogole and some related compounds by rat and mouse liver
         microsomes, Biochemica et Biophysica Acta, 673, 504-516

    Swanson, A. B. et al. (1979) Mut. Res., 60, 143-153

    Taylor, J. M., Jenner, P. M. & Jones, W. I. (1964) A comparison of the
         toxicity of some allyl, propenyl and propyl compounds in the rat,
         Toxicol. Appl. Pharmacol., 6(4), 378-387

    Trubeeck Laboratories (1958) Unpublished report. Toxicological
         screening of components of food flavors. Class IX. Aromatic
         aldehydes (Eugenol)

    Tyler, V. E., Brady, L. R. & Roberts, J. E. (1976) Pharmacognosy. Pg.
         159, Lea & Febiger - Philadelphia. 7th Edition

    Van Duuren, B. L. & Goldschmidt, R. M. (1976) Cocarcinogenic and
         tumor-promoting agents in tobacco carcinogenic, J. Natl. Cancer
         Trust, 56, 1237-1242

    Van Duuren, B. L. et al. (1966) The tumor-promoting agents of tobacco
         leaf and tobacco smoke condensate, J. Natl. Cancer Trust, 37,

    Webb, J. G. & Bussel, N. E. (1981) A comparison of the inflammatory
         response produced by commercial eugenol and purified eugenol,
         J. Dent. Res., 60, 1724-1728

    Weinberg, J. E. et al. (1972) (14C)-eugenol. I. Synthesis,
         polymerization, and use, J. Dent. Res., 51(4), 1055-1061

    Yuasa, A. (1974) Exp. studies on glucuronidation. III. Jpn. J. Vet.
         Sci., 36(5), 427-432

    See Also:
       Toxicological Abbreviations
       Eugenol (FAO Nutrition Meetings Report Series 44a)
       Eugenol (WHO Food Additives Series 14)
       EUGENOL (JECFA Evaluation)
       Eugenol (IARC Summary & Evaluation, Volume 36, 1985)