Skip to main content
. Author manuscript; available in PMC: 2022 Aug 1.
Published in final edited form as: Pharmacol Ther. 2021 Mar 18;224:107838. doi: 10.1016/j.pharmthera.2021.107838

Table 1.

Sixty-five flavoring ingredients in non-cannabis e-liquids demonstrated to induce toxic effects on cells.

Flavorings by functional group CAS # Flavor Study
Alcohols
 Benzyl alcohol 100-51-6 Floral Leigh et al. (2016); Behar, Luo, et al. (2018)
 Dipropylene glycol 110-98-5 Mildly alcoholic Behar, Davis, Bahl, et al. (2014)
 Ethanol 64-17-5 Alcoholic, rummy Otreba et al. (2018)
 Maltol 118-71-8 Sweet, Cotton candy Gerloff et al. (2017), Behar, Luo, et al. (2018), Kim et al. (2018), Muthumalage et al. (2018), Kerasioti et al. (2020), Szafran et al. (2020)
 Phenethyl alcohol 60-12-8 Fruit, Honey, Lilac Marescotti et al. (2020)
Aldehydes
 p-Anisaldehyde 123-11-5 Anise Behar, Luo, et al. (2018), Berkelhamer et al. (2019), Noël et al. (2020)
 Benzaldehyde 100-52-7 Almond Behar, Luo, et al. (2018), Berkelhamer et al. (2019), Erythropel et al. (2019), Hickman et al. (2019)
 Cinnamaldehyde 104-55-2 Cinnamon Behar, Davis, Bahl, et al. (2014), Behar et al. (2016), Bengalli et al. (2017), Clapp et al. (2017), Gerloff et al. (2017), Behar, Luo, et al. (2018), Fetterman et al. (2018), Muthumalage et al. (2018), Sassano et al. (2018), Bishop et al. (2019), Clapp et al. (2019), Hickman et al. (2019), Nystoriak et al. (2019), Noël et al. (2020), Tsai et al. (2020)
 2-Methoxycinnamaldehyde 1504-74-1 Cinnamon Behar, Davis, Bahl, et al. (2014)
 Isovaleraldehyde 590-86-3 Fruity, Nutty Berkelhamer et al. (2019)
 3-(methylthio) propionaldehyde 3268-49-3 Cooked potato, Soy Marescotti et al. (2020)
 5-Methyl-2-phenylhex-2-enal 21834-92-4 Cocoa Leigh et al. (2016)
 Piperonal 120-57-0 Cherry, Vanilla Bitzer et al. (2018)
 Ethyl vanillin (121-32-4 Floral Bengalli et al. (2017), Bitzer et al. (2018), Otreba et al. (2018), Clapp et al. (2019), Erythropel et al. (2019), Hickman et al. (2019), Szafran et al. (2020)
 o-Vanillin 148-53-8 Vanilla Gerloff et al. (2017), Muthumalage et al. (2018)
 Vanillin 121-33-5 Vanilla Behar, Davis, Bahl, et al. (2014), Behar, Luo, et al. (2018), Fetterman et al. (2018), Muthumalage et al. (2018), Sassano et al. (2018), Clapp et al. (2019), Erythropel et al. (2019), Hickman et al. (2019), Omaiye et al. (2019), Kerasioti et al. (2020), Noël et al. (2020), Rowell et al. (2020), Szafran et al. (2020)
Alkenes
 Estragole 140-67-0 Anise, Licorice Noël et al. (2020)
Arenes
 t-Anethole 4180-23-8 Anise Noël et al. (2020)
Carboxylic acids
 Propionic acid 79-09-4 Fruit Kerasioti et al. (2020)
Chromanones
 Coumarin 91-64-5 Sweet, Hay Gerloff et al. (2017), Muthumalage et al. (2018)
 Cinnamon oil 84961-46-6 Cinnamon Bengalli et al. (2017)
Esters
 Allyl-cyclohexylpropanoate 2705-87-5 Pineapple Leigh et al. (2016)
 Allyl hexanoate 123-68-2 Pineapple Marescotti et al. (2020)
 Ethyl acetate 141-78-6 Aromatic, brandy Kerasioti et al. (2020)
 Ethyl butyrate 105-54-4 Pineapple Kim et al. (2018), Kerasioti et al. (2020)
(E)-Cinnamyl acetate 21040-45-9 Sweet, Floral, Spicy Berkelhamer et al. (2019)
 Ethyl cinnamate 103-36-6 Cinnamon, Floral Behar, Luo, et al. (2018)
 Hexyl acetate 142-97-7 Apple Kim et al. (2018), Kerasioti et al. (2020)
 Isoamyl acetate 123-92-2 Banana Fetterman et al. (2018)
 Methyl anthranilate 134-20-3 Flower, Honey, Peach Marescotti et al. (2020)
 Methyl cinnamate 103-26-4 Balsamic, Strawberry Leigh et al. (2016), Berkelhamer et al. (2019)
 Methyl 3-hydroxyhexanoate 21188-58-9 Fruit Leigh et al. (2016)
 Triacetin 102-76-1 Creamy, Velvety Behar, Luo, et al. (2018), Kim et al. (2018)
Ketonesa
 Acetoin 513-86-0 Butter, Dairy Gerloff et al. (2017), Muthumalage et al. (2018), Kerasioti et al. (2020)
 2-Acetylthiazole 24295-03-2 Nut, Popcorn Marescotti et al. (2020)
 Damascenone 23726-93-4 Apple, Wine-like Sherwood and Boitano (2016)
 β-Damascone 35044-68-9 Floral Leigh et al. (2016), Bitzer et al. (2018)
 α-Ionone 127-41-3 Raspberry Sherwood and Boitano (2016)
 3-Methyl-2,4-nonanedione [D] 113486-29-6 Fruit, Hay, Straw Marescotti et al. (2020)
 3-Methylcyclopentane-1,2-dione [D] 765-70-8 Sweet, Maple, Bready Leigh et al. (2016)
 Diacetyl (2,3-butanedione) [α-D] 431-03-8 Butter, Dairy Behar et al. (2016), Gerloff et al. (2017), Fetterman et al. (2018), Muthumalage et al. (2018), Park et al. (2019)
 Pentanedione [D] 123-54-6 Buttery, Caramelly Gerloff et al. (2017)
 2,3-Pentanedione [α-D] 600-14-6 Butter, Dairy Muthumalage et al. (2018), Park et al. (2019), Kerasioti et al. (2020)
 Raspberry ketone 5471-51-2 Citrus, Raspberry Otreba et al. (2018)
Lactones
 γ-Decalactone 706-14-9 Fruity, Creamy Leigh et al. (2016), Bitzer et al. (2018)
 δ-Tetradecalactone 2721-22-4 Fruity, Creamy Bitzer et al. (2018)
Phenols
 Eugenol 97-53-0 Clove Behar, Luo, et al. (2018), Fetterman et al. (2018), Noël et al. (2020)
 Guaiacol 90-05-1 Burnt, Wood Marescotti et al. (2020), Szostak et al. (2020)
 Propenyl guaethol 94-86-0 Vanilla, anise Kerasioti et al. (2020)
Propylene glycol reaction acetals
 Benzaldehyde PG acetal 2568-25-4 Floral Erythropel et al. (2019), Hickman et al. (2019)
 Cinnamaldehyde PG acetal 4353-01-9 Cinnamon Noël et al. (2020)
 Ethyl vanillin PG acetal 68527-76-4 Dairy Bitzer et al. (2018), Erythropel et al. (2019)
 Vanillin PG acetal 68527-74-2 Floral Erythropel et al. (2019), Rowell et al. (2020)
Pyrazines
 Acetylpyrazine 22047-25-2 Toasted Cereal Fetterman et al. (2018)
 2,5-Dimethylpyrazine 123-32-0 Chocolate Sherwood and Boitano (2016), Fetterman et al. (2018)
Pyrones
 Ethyl maltol 4940-11-8 Caramel Sherwood and Boitano (2016), Behar, Luo, et al. (2018), Bitzer et al. (2018), Kim et al. (2018), Otreba et al. (2018), Clapp et al. (2019), Omaiye et al. (2019), Rowell et al. (2020)
Terpenoidsb
 Carvone [K] 99-49-0 Basil, Caraway, Fennel Leigh et al. (2016), Bengalli et al. (2017)
 Citral 5392-40-5 Lemon Bitzer et al. (2018)
 Citronellol [A] 106-22-9 Citrus Marescotti et al. (2020)
 Eucalyptol [E] 470-82-6 Camphor, Eucalyptol Fetterman et al. (2018)
 Limonene 138-86-3 Lemon Leigh et al. (2016), Bitzer et al. (2018), Noël et al. (2020)
 Linalool [A] 78-70-6 Floral, Spice Sherwood and Boitano (2016), Bitzer et al. (2018), Berkelhamer et al. (2019), Kerasioti et al. (2020), Marescotti et al. (2020)
 Menthol [A] 89-78-1 Mint Leigh et al. (2016), Bengalli et al. (2017), Behar, Luo, et al. (2018), Fetterman et al. (2018), Otreba et al. (2018), Berkelhamer et al. (2019), Omaiye et al. (2019), Kerasioti et al. (2020), Al-Saleh et al. (2020)
 Menthone [K] 89-80-5 Mint Behar, Luo, et al. (2018)
 α-Pinene 80-56-8 Cedarwood, Pine Berkelhamer et al. (2019), Marescotti et al. (2020)
 Pulegone 89-82-7 Mint, Cool Berkelhamer et al. (2019)
a

Ketones [D = Diketone, α-D = α-Diketone]

b

Terpenoids [A = alcohol, E = ether, K = ketone]