I've been reviewing your forum for info on how to strengthen the BBB, and wanted to pass along a tip I got from a specialist at IU med center. He is an MD and PhD Pharmacology who specializes in adverse drug reactions. When I told him that my daughter's severe reactions could be stopped almost instantly by Flonase, he said it made perfect sense because Flonase temporarily seals the BBB. I find that the effect lasts about an hour. If she's had a severe exposure we have to repeat. If we repeat too often, she'll start getting bloody noses. So we don't rely solely on Flonase. When she has a reaction, we use a combination of GABA, Grapeseed Extract with C (by NOW), and Magnesium - and have recently been experimenting with Ashwaganda, and Ayurvedic herb that's quite impressive! I could explain the "why" of each of those, although you guys probably already know. How many and which remedies we choose depends on what she was exposed to and the severity of her reaction, but the Flonase is absolutely indispensable in the most severe reactions. I recently learned that Flonase (Fluticasone) depletes magnesium and some other vitamins from the body. So, we are trying to use it less and less. Thus, I'm on your forum learning other methods. We're trying Thiamine, for instance, and have increased her flavenoids (Blueberry Extract by Life Extension, Bilberry Extract, and the Grapeseed mentioned above). My plan is to save Flonase for only the most severe reactions, and by being more proactive about the daily BBB support supplements, hopefully she'll have fewer reactions. I want to add for clarity that, to my knowledge, she doesn't suffer olfactory reactions. The only airborne triggers I've noticed are pesticides. However, her food and drug reactions are so severe as to have required hospitalization a few times. And she can only eat about 40 foods total - her intestinal hyperpermeability is the worse our doctor has ever seen. Complicated background. Seems to have its root in P450 deficiency and perhaps undermethylation. At any rate, I wanted to pass along the Flonase tip to those of you studying the BBB. Also, Sulforophane (broccoli extract) has quite good evidence for strengthening the BBB. Unfortunately, she can't take it due to its high cysteine content, plus she has sulfite sensitivity. I tried it myself and it made me way too hyper. But it may work for some of you. Best wishes!