Researchers developed a way to standardise the description and recording of different smells, according to a study published in the journal Scientific Data. The authors believe this could have several potential applications, including in medicine.
We all agree about the colour red or the shape of a ball, but describing odours can be more challenging. This is because, unlike the processing of wavelengths of light in the brain, which allow us to describe colours and objects, it’s not easy to deduce the smell of substances from their chemical composition. To help solve this, scientists at Friedrich Schiller University Jena, Germany compile how thousands of test subjects perceive, describe, and classify odours.
“The chemical structure of everything in our environment that we can smell is generally very complex. We are usually unable to say exactly what odour the individual chemical components emit, as the individual substances dock onto different receptors in the nose depending on their composition. For example, we don’t know how a certain amount of carbon atoms smells,” said Antonie Bierling from the Institute of Psychology at the University of Jena.
To find a solution, scientists at the University of Jena worked with colleagues at TU Dresden to create a fundamental odour database as part of the “Olfactorial Perceptronics” project. The project relies on several research disciplines, including psychology, physics, chemistry, materials science, and medicine. During the study, over 1,200 participants smelled 74 elementary (from a chemical point of view) odour samples. The participants described the smells in their own words and also used a rating scale to assess, among other things, how pleasant or intense they found the respective odour. These results can be assessed at https://crown-dataset.streamlit.app/.
The authors believe this database could have incredible applications. “Our smartphone, for example, can recognise our face or our voice – but when it comes to digital smelling, developers are still coming up against fundamental limits,” explained Alexander Croy, a physicist from the Institute of Physical Chemistry at the University of Jena. “With the help of such research results, however, we are already getting closer to the electronic nose and may even be able to identify our own body odour at some point.”
An electronic nose could have enormous applications in medicine, for example. The researchers in Jena joined forces with colleagues from Finland, Israel and the Czech Republic to develop a database specifically for body odours. The joint project “Smart Electronic Olfaction for Body Odour Diagnostics” – SMELLODI for short – is funded by the European Union. “We know that certain diseases have an impact on body odour. It can therefore be very helpful in recognising and diagnosing illnesses to record it in detail,” said Antonie Bierling. “However, this cannot be articulated well, as the vocabulary for describing body odour is still very limited.”
To create this database, the team asked over 2,600 test subjects in 17 countries how they would describe the odour of individual body parts and how it differs when a person is ill or has been exercising.
The result is a series of descriptions for various odours in 13 languages, which allowed the team to write general statements about how certain areas of the body smell. Many participants described armpit odour as sour, bad breath as stinky and foot odour as cheesy. Thanks to this database, scientists researching this field now have access to a more standardised language system for describing odour perceptions. This database can also be accessed online (https://bow-descriptors.streamlit.app).
Bierling, A.L., Croy, A., Jesgarzewsky, T. et al. A dataset of laymen olfactory perception for 74 mono-molecular odors. Sci Data 12, 347 (2025). https://doi.org/10.1038/s41597-025-04644-2