So it was with interest that I read this article which investigated whether a simple "leaves extract" would be able to help this group of sufferers. A randomized, double-blind, active comparator study was done, to evaluate the effectiveness of two Rosmarinus officinalis and Platanus orientalis
Clinical evaluation showed that cough, sputum production and wheezing were significantly inproved in the group taking the rosemary herb extract.
Now I know that many people would say that leaf extract and essential oils are 2 entirely different substances, and yes they are, but the chemical compounds are still within each substance. A study of inhalation of rosemary oil did show a relaxation of the tracheal smooth muscle was shown. This would back up the suggestion that rosemary e/o would be beneficial for asthma sufferers especially those who are regularly inconvenienced by visits to hospital. what have they got to lose? 10 mls of Rosmarinus officinalis E/O is less than a fiver.
Mirsadraee M, Tavakoli A, Ghorani V, Ghaffari S. Effects of Rosmarinus officinalis and Platanus orientalis extracts on asthmatic subjects resistant to routine treatments. Avicenna J Phytomed. 2018 Sep-Oct;8(5):399-407. PMID: 30345227; PMCID: PMC6190250.