The human nose can detect one trillion different odours, far more than we previously thought, say US scientists.
Until now, the long-held belief was that we can sniff out about 10,000 smells.
New estimates published in Science, external suggest the human nose outperforms the eye and the ear in terms of the number of stimuli it can distinguish between.
Researchers at the Rockefeller University say we use only a tiny part of our olfactory powers.
The human eye uses three light receptors that work together to see up to 10 million colours, while the ear can hear almost half a million tones.
Until now it was believed the nose, with its 400 olfactory receptors, could detect only about 10,000 different odours.