Can taking too many vitamins be really dangerous?

Ok I have a friend who has a really severe OCD called Scrupulosity, which can make her think things compulsively and on religious topics that make her horribly depressed, and it really has been ruining her life for a long time now...

Well about a week ago she started taking a 1 A Day Woman's vitamin pill and apparently it really helped her settle down her racing thoughts... well today she told me that she's apparently taking 2 a day!!! Now I avoid taking medications, even vitamins unless necessary and she's really not listening to me when I tell her that what she's doing is dangerous. So here is my question... can taking 2 One A Day Woman's Vitamin's be really dangerous?

Probably not 2, but look into it more.
If it gets higher than that, she has to stop. It is possible to overdose on vitamins.

It is best to take the recommended dosage listed on the bottle.
However, two a day won't harm her - she will just void anything excessive thru urine & bowel movements.

Now, if she gets forgetful & starts taking excessive numbers of them, yes, it can be bad for her. Taking excessive amounts of anything can be harmful.

probably not harmful.

Why not substitute the real vitamins for a homoeopathic one? Tell her it's better and she can then take as much as she likes.