Tell her that tattoos doesn't suit good girls.  It suits gangsters.  when people see tattoos on girls, they think of that girl as cheap who is out there to get attention from bad guys

I think that the attitudes of people like rahil4u is exactly why your niece is choosing to express herself with tattoos. The best way to truly show concern for someone's future is not to tell them that they are cheap or to put them down. Simply explain to her why you think that it may affect her future. Explain that it can cause serious problems when trying to go into a business oriented career, as well as it may affect the way that some look at her... like rahil4u above.

 

She does this because she is an adult and she feels that it is okay. Belittling her will only encourge her to do it more, and leave you out of her life more as well! She is an adult and it is her decision to get tattoo's if it is what she wants! You can care and have concern for her, but you must always respect her right to make her own decisions.

You can't. She will eventually grow up and find out that her tattoos are keeping her from having all of the opportunities that she would otherwise have, keeping her from potential friends, lovers and jobs. She will then have to go through years of painful laser treatments when she finds out what she has robbed herself of. It's natural to want to protect her from all of that, but sadly, you can't. She will have to learn all of it for herself because she's legally an adult now.

Tell her that it's not nice. Frightened her by saying it may affect her health.

It's enough already and whole body covered with tattoos may affect her personal image.

Just for fun,ok. Don't get addicted to it.

It is her personal choice, but you can help by pointing out future soical situations where the tatooes may interfer with her leading a normal life.

And if she has her heart set on them, make sure she gets them done at a hygeinic place.

I agree with teenskee, you should not be too hard on your niece.Don't put her on the defensive side and don't give her the impression that you are against what she's doing. You talk to her as if having a tatoo is not a big deal by doing so you're actually sending out silent message to her that there's nothing wrong and she can tell you openly what she feels generally and what motivates her to have paint on her body...Is it her way of self-expression, a way to cope up with her peers, following the trends... just let her open up. Then share your own knowledge about tatoo, its history, what is it all about.Then slowly tell her that people and society always change.. Tell her that  society changes and today it has this "negative" attitude towards tatoo as it is commonly associated with rebels, gangsters and prisoners. Tell her softly that maybe 10 tatoos are enough to achieve whatever her goal is, in having tattoos.

At this age, young adults tend to express their emotions a little bit less. Your niece might be having some emotional problems that she could not speak out or could be because of peer pressure or just plain rebellion. The best thing to do is to confront her, in a way that you are not dictating or commanding or telling her that what she's doing is wrong. Have an approach that will actually make her listen to you. Show her that you are concerned and try asking her the reason behind those tattoo's. Tell her the pro's and con's of wearing a tattoo. Tell her the long term effects. On her physical aspect, how this will affect her in the future, how hard it is to remove and the actual pain of getting one, the difficulty of finding a decent job and how the society will look at her. Tell her that she looks perfect without those tattoos and she doesn't really need one. Appreciate her. Advice, never command.

Well I have to agree that trying to persuade won't help. We, humans, like to do the opposite- if we are told to beware of something, we become curious. It is really an unpleasant situation, but trying to make her to change her mind will only tear you apart. Or you can try to propose something else which is not allowed - maybe she will switch her thoughts to it!