Yerba maté (also known simply as maté) is a tea made from the dried leaves of Ilex paraguariensis, an evergreen shrub in the holly family that grows in Central and South America. It has a long history as both a beverage and as a treatment for ailments such as fatigue, appetite control and a weakened immune system. Recent evidence has furthered maté's health benefits by highlighting its potential as promoting healthy bones, specifically preserving bone mineral density in postmenopausal women.
An Argentine study published in the January 2012 issue of the journal Bone compared 146 postmenopausal women, some of whom who drank one liter of yerba maté tea daily for five years and some of whom didn't. Results showed that the yerba maté drinkers had 9.7 percent higher bone density in their lumbar spine and 6.2 percent higher bone density in the area of the thigh just below the hip joint than the women who didn't drink the tea.
If you do want to drink yerba maté for its health benefits, or simply because you enjoy the taste, be aware that it may cause a stimulant effect since maté contains xanthenes, a class of chemical compounds that includes caffeine.