Originally Posted by VitaminH

I've been taught in Pharmacy school that the forehead ones are crap. The mouth ones work, but you've got to get them in the right spot. Most need to be stuck off to one side of that little flap of skin holding your tounge to the floor of your mouth and all the way back, into the sort of pocket back there to get a good reading. Also be sure you don't drink anything or talk to much for a good 10 min before taking it, else your mouth could be cooler than your body temp.


addendum: If you're going through hot/cold phases then you've probably got a fever.