Simplify the following text for a Grade 10 native English-speaking person.
Original: Aromatherapy is a form of alternative medicine that uses volatile plant materials , known as essential oils , and other aromatic compounds for the purpose of altering a person 's mind , mood , cognitive function or health .
Simplified: Aromatherapy is a type of alternative medicine that uses the part of plants known as essential oils . Some people think that aromatherapy helps to change a person 's mind , mood or health but this has n't been proven scientifically .