Steam Inhalation of Herbs

I am interested in starting to vaporize (inhale gases passed by herbs into lungs; not smoke) these types of herbs: Damiana Herb, Mullien Herb, Red Clover Flowers Herb, Spearmint Herb, and Wild Lettuce Herb. And I was wondering if there is any harmful effects of doing this? And should I ask my doctor if this will be bad for my health?

There is along tradition of inhaling the vapours from aromatic herbs when infused in boiling water. This method of administering herbs is particularly healthful and helpful for the lungs and the entire respiratory system. Any herb that has a high volatile oil content would work - these are the strong smelling herbs peppermint, lemon balm, catnip, oregano,thyme, lavender, sage, spearmint, etc. The non aromatic (no strong odor) herbs would best be administered via a tea or tincture (alcoholic extraction of the medicinal properties). Damiana, mullein, red clover and wild lettuce are non aromatic herbs thus best if taken as a tea or tincture.