The brain encodes odors received via the nostrils as originating from the nose but smells detected through the back of the throat activate regions of the brain linked with signals from the mouth. Because most taste involves odor going to olfactory receptors in your brain, it stands to reason that if you can't smell, you won't be able to taste anything at all. If you can't smell because of a head cold, smoking, drug side effects, or a broken nose, your olfactory receptors may be too damaged, obstructed, or inflamed to transmit signals up to your brain.