Foot odor due to microbial metabolism and its control

Can J Microbiol. 2006 Apr;52(4):357-64. doi: 10.1139/w05-130.


To characterize foot odor, we analyzed its components by sensory tests, isolated microorganisms that produce it, and evaluated the mechanism of the occurrence of foot odor. As a result, foot odor was found to be derived from isovaleric acid, which is produced when Staphylococcus epidermidis, a resident species of the normal cutaneous microbial flora, degrades leucine present in sweat. In addition, Bacillus subtilis was detected in the plantar skin of subjects with strong foot odor, and this species was shown to be closely associated with increased foot odor. Therefore, we screened various naturally occurring substances and fragrant agents that inhibit microbial production of foot odor without disturbing the normal microbial flora of the human skin. As a result, we identified citral, citronellal, and geraniol as fragrant agents that inhibit the generation of isovaleric acid at low concentrations.

MeSH terms

  • Acyclic Monoterpenes
  • Adult
  • Aldehydes / pharmacology
  • Amino Acids / analysis
  • Anti-Bacterial Agents / pharmacology
  • Colony Count, Microbial
  • Dose-Response Relationship, Drug
  • Female
  • Foot / microbiology*
  • Humans
  • Leucine Dehydrogenase / antagonists & inhibitors
  • Leucine Dehydrogenase / metabolism
  • Lipid Metabolism / drug effects
  • Lipids / analysis
  • Microbial Sensitivity Tests
  • Molecular Structure
  • Monoterpenes / pharmacology
  • Odorants*
  • Plant Extracts / chemistry
  • Plant Extracts / pharmacology
  • Skin / microbiology
  • Staphylococcus epidermidis / drug effects
  • Staphylococcus epidermidis / isolation & purification
  • Staphylococcus epidermidis / metabolism*
  • Sweating / physiology


  • Acyclic Monoterpenes
  • Aldehydes
  • Amino Acids
  • Anti-Bacterial Agents
  • Lipids
  • Monoterpenes
  • Plant Extracts
  • Leucine Dehydrogenase
  • citronellal
  • citral