[fso301]

I've took niacin as a supplement a few years ago, and it caused my face to flush and I felt feverish for an hour or so

Sounds like a typical response to niacin.

[Welsh Rabbit]

Sounds like a typical response to niacin.

From all the responses I've gotten on this this thread, I see I most likely didn't have an allergic reaction, but a normal response to the vitamin. It's just a bit off putting because there are not many supplements that have that kind of reaction to the normal person.