Aromatherapy is a type of complementary medicine that uses volatile plant materials or essential oils,  for the purpose of improving a person's mood, function or health. Scientific evidence is growing in all these areas. An aromatherapist is the person who performs  aromatherapy.  Two mechanisms are offered to explain the effects. One is the influence of essential oil aromatics on the brain, especially the limbic system .This is achieved by direct inhalation of the aromatherapy oil as it volatalizes. The other is the pharmacological effects of the essential oils as they are absorbed through the skin.  Some of the aromatherapy oils used have proven and recognised antifungal and antibiotic properties ( an example would be tea tree oil). Other oils have direct physiological effects ( eg eucalyptus oil has a direct effect on the the nasopharyngeal cavities).In many countries, essential oils are included in the national pharmacopoeia,