Wilson's disease (WD) is a rare autosomal recessive disorder caused by mutations in the copper-transporter ATP7B and characterized by the maldistribution of copper, including accumulation in the liver and the brain. WD patients are known to have reduced general olfactory function, especially those with neurological symptoms.1, 2 Furthermore, it might be suspected that WD patients in particular have a missing or reduced olfactory perception of sulfur compounds according to a series of anecdotal reports from patients, who exhibit a lack of perception of, for example, rotten eggs, the smell of flatulence and secretions of the skunk. Based on in vitro findings, it has been proposed that the presence of copper is essential for olfactory perception of sulfur compounds by odorant receptors in the nasal cavity.3, 4 We investigated whether sulfur perception is altered in WD patients when compared to age-matched healthy controls (HC).