Oregano oil under the tongue? That's too hot! Better to put in water and swallow it. After all, it's not sublingual, tinctures are meant to be digested. But it's mainly antifungal, not for allergies. As for allergies, since it's an immune system disorder, it's not dependent on your family history -- it's very individual. People are exposed to different immune system disrupters and diets, and so they will have different immune system problems.