I use valerian every night and have no side effects at all. With long-term usage you do tend to get tolerant, but you can adjust the amount you take. I love valerian. It helps me sleep more soundly, and if I do wake up at night, it helps me get back to sleep more easily. I also keep some on hand for days when I'm really stressed or feeling anxious. One 400 mg cap helps take the edge off things. I use it rarely for this reason, but it's nice to have on hand.
Everyone is entitled to his or her informed opinion. --H. Ellison