Is there a reason why having prolonged dry mouth makes you nauseous?

Yes but why?: A dry mouth can produce an increase in the density of the normal nasal sinus drainage and that can produce nausea. The question is why the mouth is so dry, is related to medicines, poor fluid intake or other condition?. Could nausea be related to gastric reflux and dry feeling of the mouth due to that. Might need to look a little further. Best!!