My husband has constant sweet taste in mouth x 4-5 days- had cbc, glucose, thyroid,cholesterol, all negative 1 year ago. what could cause this?

Constant Sweet taste: in the mouth may be due to some insult on the taste buds on the back and edges of the tongue. This can result from extreme temperature exposure, chemical exposure, acidic food, acid reflux, infection, etc. If the problem has not resolved in couple of weeks or is recurrent, consider consulting a physician, as it can be a sign of more serious disease.

IF it persists> ENT: Diagnosing the cause of taste disorders can be challenging, but fortunately most often the disorder is temporary. Persistent taste disorders on the other hand require evaluation. Some causes are: GERD, oral infections, sinusitis, problems with dentures, upper respiratory infections, ketosis, olfactory auras due to Temporal lobe epilepsy, Frontal lobe brain tumors and a number of other causes.