I can't really tell you how long to take it, I have taken it for upto a year an half straight without a break (1tsp a day is what I like). You have to work up from a small dose, as what MH describes is very true, the Olive leaf will drive herpes right out of your spine, and you will end up with a HUGE outbreak on your mouth (if you carry the herpes simplex that is, most have it these days). I have at least 6 times now been off olive leaf for a long time, then started to get sick, and took several huge doses (as it will wipe the sickness out) and had a huge cold sore outbreak, In a way I can really appreciate the outbreak (I immediately put pure oregano oil on the pre burst bumps, and usually they will go dry up) as it shows me just how powerful olive leaf really is!
If you continue to take it on a ongoing basis, once you build up, you will have no problem! I like MH believe, in the world we live in, it is wise to take it daily to ward of future problems.
If I had Epstein Barr, lymes, HIV, morgellas or any of these insane viruses, olive leaf would be my #1 form of attack, I have seen how hard it works!
I am also learning about neem leaf right now, I will report what I learn! If any others have info, please share!
On the olive leaf, if you can find a tree, and pick it fresh, that is the most powerful of course! I take a fresh leaf and stick it under my tongue, chewing it every 20seconds or so (it is very acrid) after a couple minutes it will just fall apart, and you can chew it up and swallow it! I have done this up to 3 times in one day for a mega dose to heal a breast infection, it was gone in a few hours (even with antibiotics it usually takes 3 days).
BTW I have been using olive leaf for about 8 years now!