Olfaction, or the sense of smell, is the chemical sensation of gaseous odorants that allows us to perceive smells. The olfactory nerve, in coordination with other neuroanatomical structures in the nasal passages, neurotransmitters, and the cerebral cortex, is responsible for carrying out this intricate chemosensory process. Olfaction has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste. It is also critical for evaluating the safety of ingestible substances, assessing impending danger, and recognizing social relationships. Insect olfaction refers to the function of chemical receptors that enable insects to detect and identify volatile compounds for foraging, predator avoidance, finding mating partners (via pheromones), and locating oviposition habitats. The process of olfaction involves the conversion of a chemical stimulus, an odorant, into an electrical signal sent to the brain for interpretation. Olfactory problems can be divided into different types based on their malfunction, including total olfactory dysfunction (anosmia), incomplete olfactory dysfunction (partial anosmia, hyposmia, or microsmia), distorted olfactory function (dysosmia), and spontaneous sensations like phantosmia.