Peppermint : Mentha piperita
Part Used: leaves
Method of extraction: Distillation 
Therapeutic properties: Peppermint oil is promoted for topical use (applied to the skin) for problems like headache, muscle aches, joint pain, and itching. Peppermint aromatherapy can help unclog your sinuses and offer relief from a scratchy throat. It acts as a refreshing expectorant.