I take a cigar every now and then for 3 months and today after smoking i noticed blood it dosen't hurt but got me scared.both of my parents smoke.

Good: You should be scared. Smoking causes cancer which should scare you. Stop smoking now. See your doctor to get checked out as to the cause of the blood. http://www.webmd.com/cold-and-flu/flu-guide/adult-flu-symptoms

May be serious...: but your question cut off (where did you notice blood?). I cannot think of too many health benefits to tobacco smoking. You've been appropriately scared, now exert your will power and quit smoking. "The best way to break a habit is to drop it." Leo Aikman