What is the third gift of kings?

The Magi gave three gifts to the newborn Jesus: gold, frankincense and myrrh. We are clear about what the first two are. And the other one? Mirra is an aromatic resin, the sweat of the tree Commiphora myrrha, which grows naturally in northeastern Africa, Arabia and Turkey. Its taste is very bitter, but in ancient times it was a precious article, as it was used for perfumes and ointments. This substance has many healing properties that were used against scratching, dysentery and parasites. And, as Diskorides collected it in Medical Matter in the 1st century, it is also an abortion. Did the Magi want to send the new parents a subliminal message?