The ancient Druids believed mistletoe had miraculous healing powers. It was placed over doorways to ward-off evil and to bestow health, happiness, and luck. The custom of embraces and kisses at doorways co-evolved with the hanging of doorway mistletoe. Mistletoe has long been used as a medicinal herb but also has some very toxic components so always keep it out of reach of young children.
Mistletoe is also a parasitic plant that can damage forest evergreens. Mistletoe that grows in the Rocky Mountain forests has no need for chlorophyll as it is totally parasitic and has a yellowish cast. It is generally viewed as a pest on evergreens.