Trekker
There are PHYSICAL dangers of yoga which many doctors who promote it don't seem to be aware of, including stroke, spinal damage, retinal tearing, and other brain damage. This Christian article is about the SPIRITUAL dangers:
http://www.christianpost.com/news/hypnosis-and-yoga-open-hidden-spiritual-doors-75641/
P.S. Also mentions the dangers of DREAM CATCHERS, HYPNOSIS, and the occult in general.