A method and apparatus (22) for treating culinary gaseous effluents (Eg) carried in an air extraction duct of a kitchen, the apparatus includes: a unit (24) for storing in liquid form a nucleophilic active product (Pa), or odour destroyer, able to fix foul-smelling molecules in the form of inert salts, a nebulizing and diffusing unit (26) which vaporizes or sublimates the active product (Pa) coming from the storage unit, and which diffuses the vaporized or sublimated active product (Pa) in an extraction duct (18), at ambient temperature, so as to minimize the discharge of foul-smelling molecules at the outlet of the extraction duct. A plant including this apparatus is also disclosed.