I have been taking the capsules daily as a supplement since September and usually by this time of the year, I will have contracted one or two viruses. I am a type 2 diabetic, have allergies and asthma - and in addition I work in a middle school! Bugs and germs are rampant in this setting and I have sucessfully held them off this winter; anecdotally I would have to say the elderberry extract is improving my immune system.