Aromatherapists combine essential oils with a vegetable oil and use the mixture as a liniment for massage. The oils also may be spread throughout a room by a diffuser or humidifier, and inhaled with the steam created. Essential oils are often used in small amounts in a soaking bath or hot tub. It is believed that health can be improved as the oils are absorbed through the skin or through the sense of smell. Scientifically, it is known that even small traces of a single scent can activate receptors or nerve cells in the nasal cavity.
Impulses go from there to the olfactory bulb in the brain.
Different odors have been found to be identified with communication and memory. Odors can have powerful influences. They can trigger memories from the past. Chemical substances called pheromones emitted by all humans are picked up as odors by others. These odors, often unconsciously, play a role in sexual attractions.