Mebendazole (C16H13N3O3): structure, properties and hazards

Names and identifiers

IUPAC name: methyl N-(6-benzoyl-1H-benzimidazol-2-yl)carbamate
Synonyms: Vermox, anthelmintic, Ovitelmin
+ 36 more
Pantelmin, Telmin, Mebenvet, Vermicidin, Vermirax, Verpanyl, MBDZ, Besantin, Noverme, Mebendazol, Mebendazolum, Methyl 5-benzoyl-2-benzimidazolecarbamate, methyl N-(6-benzoyl-1H-benzimidazol-2-yl)carbamate, 5-Benzoyl-2-benzimidazolecarbamic acid methyl ester, Emverm, Carbamic acid, (5-benzoyl-1H-benzimidazol-2-yl)-, methyl ester, Methyl 5-benzoyl-2-benzimidazolylcarbamate, Zhihuanqing, R 17,635, Methyl 5-benzoyl benzimidazole-2-carbamate, R 17635, DTXSID4040682, NSC 184849, (5-Benzoyl-1H-benzimidazol-2-yl)-carbamic acid methyl ester, methyl N-(6-benzoyl-1H-1,3-benzodiazol-2-yl)carbamate, NSC-184849, 81G6I5V05I, 2-Benzimidazolecarbamic acid, 5-benzoyl-, methyl ester, R-17635, NSC184849, CHEBI:6704, DTXCID2020682, Anti Worm, mebendazolo, Telmintic, Telmintic Powder
Molecular formula: C₁₆H₁₃N₃O₃
Empirical formula: C₁₆H₁₃N₃O₃
Molecular weight: 295.29 g/mol
Exact mass: 295.09569
CAS number: 31431-39-7
PubChem CID: 4030
Canonical SMILES: COC(=O)NC1=NC2=C(N1)C=C(C=C2)C(=O)C3=CC=CC=C3
Isomeric SMILES: COC(=O)NC1=NC2=C(N1)C=C(C=C2)C(=O)C3=CC=CC=C3
InChI: InChI=1S/C16H13N3O3/c1-22-16(21)19-15-17-12-8-7-11(9-13(12)18-15)14(20)10-5-3-2-4-6-10/h2-9H,1H3,(H2,17,18,19,21)
InChIKey: OPXLLQIJSORQAM-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: Off-white amorphous powder[2]
2 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Mebendazole is a white to slightly yellow powder. Pleasant taste. Practically water insoluble. (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–shown Off-white amorphous powder [2] Hazardous Substances Data Bank (HSDB)cites Andrews P, Harder A; Anthelmintics. in: Ullmann's Encyclopedia of Industrial Chemistry. Copyright 2002 by Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim. Article Online Posting Date: June 15, 2000.
Melting point: 288.5 °C (551.3 °F, NTP 1992)[1]
Solubility in water: In water, 7.13 × 10¹ mg/L at 25 °C[2]
2 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Practically insoluble (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–shown In water, 7.13X10+1 mg/L at 25 °C [2] Hazardous Substances Data Bank (HSDB)cites Yalkowsky, S.H., He, Yan., Handbook of Aqueous Solubility Data: An Extensive Compilation of Aqueous Solubility Data for Organic Compounds Extracted from the AQUASOL dATAbASE. CRC Press LLC, Boca Raton, FL. 2003., p. 1033
log P: log Kow = 2.83[2]

Value	As written	Source
–	Mebendazole is a white to slightly yellow powder. Pleasant taste. Practically water insoluble. (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–shown	Off-white amorphous powder	[2] Hazardous Substances Data Bank (HSDB)cites Andrews P, Harder A; Anthelmintics. in: Ullmann's Encyclopedia of Industrial Chemistry. Copyright 2002 by Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim. Article Online Posting Date: June 15, 2000.

Value	As written	Source
–	Practically insoluble (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–shown	In water, 7.13X10+1 mg/L at 25 °C	[2] Hazardous Substances Data Bank (HSDB)cites Yalkowsky, S.H., He, Yan., Handbook of Aqueous Solubility Data: An Extensive Compilation of Aqueous Solubility Data for Organic Compounds Extracted from the AQUASOL dATAbASE. CRC Press LLC, Boca Raton, FL. 2003., p. 1033

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

Calculated

Heavy atoms: 22
Rings: 3
Aromatic rings: 3
Fraction sp³ carbons (Fsp3): 0.06
H-bond donors: 2
H-bond acceptors: 4
Rotatable bonds: 3 computed here · PubChem 4
TPSA (Å²): 84.1
Formal charge: 0
XLogP3: 2.8 PubChem
Complexity: 423 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C65.08%
H4.44%
N14.23%
O16.25%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: 2.97 Crippen (Wildman and Crippen 1999)
log S (water solubility): -3.85 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 2.03 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 295.3
log P ≤ 5 (Crippen): 2.97
H-bond donors ≤ 5: 2
H-bond acceptors ≤ 10: 4

Passes all four rules.

¹³C NMR shifts, predicted

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

Warning

Most widely reported: 77 company reports to ECHA. Source [3].

Harmful or irritant
Health hazard
Environmental hazard

H302Harmful if swallowed (98.7% of reports)
H341Suspected of causing genetic defects (10.4% of reports)
H400Very toxic to aquatic life (14.3% of reports)

Precautionary statements: P203, P264, P270, P273, P280, P301+P317, P318, P330, P391, P405, P501

First aid

Eyes: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. If symptoms (such as redness or irritation) develop, immediately transport the victim to a hospital. Skin: Immediately flood affected skin with water while removing and isolating all contaminated clothing.[1]

Storage

Commercially available mebendazole chewable tablets should be stored at 15-25 °C in well-closed containers ... .[2]

Safety data sheets on the supplier’s page: AbaChemScene, TargetMol, AKos Consulting & Solutions.

Always read the supplier’s safety data sheet before working with it.

Spectra

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
[2]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[3]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[4]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[5]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[6]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[7]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
[8]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.

Similar structures

Albendazole 46%

Tanimoto similarity on Morgan fingerprints (radius 2) with RDKit 2026.09, at least 45%.