Essential oils - aromatherapy--what are benefits?

Different effects. Some essential oils (or aromatherapy) can be calming and reduce stress -- such as lavender and lemon balm. Others may increase alertness, such as rosemary. Often they can be mixed with neutral carrier oils and massaged into the skin; also, they can be diffused into the air. Clinical studies are mixed -- so use them if you enjoy them, but don't rely on them alone for "a cure.".