If the medicinal flavor you are pertaining to is bandaidy then it is a phenol issue stemming from a couple of different reasons. Could be a bit of chlorine from tap water, could be from yeast stress. I had this issue with a couple of batches. I have since purchase Potassium Dimetabisulfite and with any tap water used (usually for rinsing) I use 1/4 tsp to clear out any Chloramines that can cause Bandaid.
Not a fun thing to be drinking. Won't hurt you, just won't taste at all good. Getting rid of 5 gals of the stuff is a tuff pill to swallow, dumping or drinking. Unfortunately bandaids will hang around forever, so no waiting this evil out.