Should I stop hanging out with my friend because she does drugs?

My friend just turned 19 and now wants to start experimenting with drugs. LSD, weed, and crystal. Shes hanging out with the loser drug types now and I don't know if I should still be friends with her. I'm scared that shes going to drag me into this type of lifestyle. I'm disgusted by her behaviour and worry about her all the time. Do you think shes more trouble then shes worth?