What are the effects of taking salvia divinorum?

Recently, I have heard about a new hallucinogen available called salvia dinorium. Some of my friends have tried it and they tell me it is an incredible experience and that when you hallucinate, you have the perception of being brought back in time. Before I even think about trying this, however, I would like to have a more precise idea of what the effects are and what the possible risks of taking salvia are.


Do I need to use condoms if my boyfriend might have an STI and not know it?

If my partner and I have been monogamous for three years (and I was a virgin before we met) and my partner tested negative for the HIV virus (twice, about two years ago, with a six-month gap between the tests) is it safe for us to use a birth control method other than a condom? That is, are there still any STDs that my partner might have without knowing it, that we should be worried about, even though nothing whatsoever has seemed wrong with either of us for three years and my partner has had several regular annual physicals in that time?