Disorders of the chemical senses are frequent. They can severely affect our lives. Appropriate testing is needed to determine the nature of the patient's complaints. Because many chemosensory disorders are secondary to a wide variety of diseases, olfactory or gustatory complaints may help in establishing certain differential diagnoses, e.g. in Alzheimer's disease. In turn, treatment of the underlying diseases may restore chemosensory function in these patients. Future developments appear possible in light of the availability of standardised tools for the assessment of chemosensory dysfunction.