Sage is great, but remember, it's a powerful treatment, so there are things you need to be careful about.
Some people think if it's not a "real" medication that they can just take as much as they want without consequences, but it simply doesn't work that way.
Sage has it's side effects just like anything else. For example, many people actually find that sage leaf can actually exacerbate stomach problems if taken on an upset stomach, and others develop contact dermatitis just by touching it.
More seriously, those who are pregnant or nursing should not take sage or eat things with sage leaf in them, since it can induce contractions, and has also been known to dry up breast milk.
So just remember, just because it's not pharmaceutically based doesn't mean that you can take it at will. You should consult a doctor before beginning any kind of sage supplement or infusion, just as you would with any other kind of medicine.