Why would someone, presumably quite wise, feel the need to bring the tree resins frankincense and myrrh to a woman who had recently given birth? If the time is about two millennia ago and the location is in the Middle East, these two spices were likely quite welcomed and entirely expected. Why?
Our ancestors were intimately aware of the beneficial effects of plant extracts for the treatment of pain and discomfort associated with giving birth.
Myrrh - isolated from the dried resin in the bark of either Commiphora myrrha or C. gileadensis, shrubs found in Somalia and throughout the Middle East - was historically used in liniments, including in Chinese medicine (called Mo Yao), to treat the symptoms of arthritis and as an antiseptic ointment. The Egyptians used it to embalm mummies.
The small tree is quite aromatic. The resin contains myrcene, camphorene and a series of guggulsterols as well as many other essential oils that are chemically similar to catnip. Together, these compounds produce an analgesia, or pain reduction, that is slightly more potent than morphine and may act via the brain's own endogenous opiate receptors. The resin also has an anti-inflammatory action similar to aspirin.
Myrrh may also have another valuable action that would greatly benefit any women who had just given birth; it may enhance blood clotting and would reduce post-partum bleeding.
Finally, the wise men are almost always depicted as traveling via camel at night following a celestial beacon. There's another good reason they might have traveled in the dark - the contents of the resin are unstable in sunlight!
Frankincense can be extracted from the Boswellia sacra tree that grows in Somalia and Saudi Arabia. The resin is edible and contains a pair of boswellic acids and terpenes that may be responsible for its mild anti-inflammatory action. Not surprising, extracts of the resin were popular as a treatment for arthritis in ancient Egypt. In addition, a recent publication in the journal FASEB suggested that one component of this resin, incensole acetate, also displays anti-anxiety and anti-depressive properties similar to those produced by Valium and Prozac, respectively.
Thus, in ancient times, frankincense and myrrh were commonly used together to relieve post-partum pain and anxiety, lessen the probability of post-partum depression and reduce bleeding after delivery. Whatever was left over was usually burned as incense and, as immortalized in the Christmas story of the three wise men, was highly valued as a gift. Now you can understand why.