How do I stop someone from lying?

I'm not sure but I think my sister might be a pathological liar.
She cant say 3 sentences without saying something false. She likes to make up stories to get laughs or attention from her friends. It's getting to the point that I can't trust a thing she...

says to me.
Some stories she tells are just so outrageous that they couldn't possibly be true. She has her best friend believing that she has a brother ( we don't ). She told her current boyfriend that she's deaf in one ear. In high school she told everyone that she was a year younger because she skipped a grade. This isn't just recent, she's been lying all her life, in kindergarten my parents went to pick her up and she told the teachers that they weren't her parents, her parents were dead. The list goes on and on. She tries to get me to vouch for her when I'm around her friends and she tells a lie - I just ignore her.
What do you think I can do about it?

Well, if your like me, and let's hope not, since I am be a bit cruel to lairs and cheaters, I would try to get your parents in on an act and find something she likes, get one of yours friends over, or someone you know, who she doesn't know, but someone she might like. If she tries to impress him with a lie you can set her up with basic plans or something that is so deceptive that can scare her into never lying again.

But that's what I would do, but I can't quite go into details about what I would do since I like to get very deep with those kinda situations. But scaring someone out of lying usually tends to work pretty well, trust me. =)

Dear pinkbull6,
She is doing this for a reason...what that reason is only she can know and perhaps only know with counselling. She is looking for some type of attention that she may feel she never got. She may think she has a very boring life and needs to spice it up and impress people. She needs to seek out counselling to help with this...this type of behaviour will cause her much sorrow with relationships her entire life. Just remember and this is hard not to take it personally and do not entertain her lies. When she is caught in one let her know you disapprove of it.
Sue...good luck

thanks guys! :D