Charak Samhita
अत्यादानमनादानमोकसात्म्यादिभिश्च यत्। रसानां विषमादानमल्पादानं च दूषणम् ॥१२४॥
Olfactory faculty also gets impaired by the enjoyment of smells too mild and too sharp or by absolute nonutilization of this faculty.
english translation
atyAdAnamanAdAnamokasAtmyAdibhizca yat। rasAnAM viSamAdAnamalpAdAnaM ca dUSaNam ॥124॥
hk transliteration by Sanscript