I love the smell of Frankincense- it has always had a meditative, calming affect on me. I like to light up some Frankincense and Myrrh incense when I'm feeling tense or anxious, because that's precisely what Frankincense does- calms and eases tension.
According to Roberta Wilson's "Aromatherapy for Health and Beauty" (Avery Books):
"Frankincense oil can help to fortify a mind burdened with mental anxiety, nervous tension or stress. It revitalizes the body and mind... comforts and soothes the emotions and helps you sever ties with the past that are hampering your personal growth."
Frankincense has been used since the beginning of time. It comes from the Boswellia Tree found in Oman, Yemen and the parts of Somalia. The resin is "tapped" 2 to 3 times a year and the best quality resin is considered to be Omani.
You can purchase it in granules, essential oil or incense. You can use a diffuser for the oil, or add a drop to your bath.
Boswellia has other medicinal uses, but that's a different post.
NOTE: Not to be used during pregnancy, as with many different herbs etc.