I can only base this on my DH's reaction to low carbing and degongestants. He's on a daily dose of Rynatan (prescription decongestant) and Rhinocort. He hasn't noticed any problems with either. He has noticed, however, that his allergies do seem to be better with the addition of low carbing than they were before with just the medication alone. Unless, of course, he's eating something that he's allergic to!