Natural pheromones are odors used for attracting sexual partners and communicating among lower forms of animals. Generally, scents and odors are used for cooking flavors and to taste other food varieties. The olfactory bulb of the brain is located near the amygdala and the hippocampus - the former being the seat of emotion and arousal while the latter being the seat of consolidating long-term memories.

Other pleasant smells are used to improve the general well-being of the mind and body. Disgusting smells on the other hand are essential for identifying poisons or things with negative gastronomic health effects. Because of this, there is a close and significant relationship between smell, emotions and memory.

An example of chemicals which create a variety of human sensory, perceptual and emotional experiences are essential oils. According to Darwininan theory of evolution, smell is important as a basic form of survival - to detect and discriminate smells which signal danger or threat to life, or safety and nourishment to the body. The olfactory system is the most primitive sense organ of the human body.

It is the simplest organ to understand, and it has the most direct route to the cortex for processing olfactory sensory information.