Hi again, Eric - thanks for responding.
As it turns out, I have do not have any experience with mullein tea so, on a personal / professional level, I am unable to assist you there.
However, I have (lately) seen many comments on mullein tea on our asthma Facebook platform. If you are interested, you may want to look around our community website on Facebook (there is a link at the bottom of this page). As well, now that I know you have some interest, if I should see a comment moving forward, I will be sure to check back here an provide you with a link.
Warm regards,
Leon (site moderator asthma.net)