OK, here I go again!!!
You first have to identify the ant. TERRO does work with sugar ants. But, do you have sugar ants? Generaly, ants in the bathroom are either carpenter ants or fire ants. You can tell by the size and color. Also, ants dont always come inside due to dryness OR rain. They come in for a food source. Look in your yard first...is there evidence of them? Look WHERE they are coming in the bathroom...plug the holes, calk or even vasilene works. Next, spray your yard and around the foundation. If that fails, do yourself a favor, call an exterminator. I learned about ants the hard way!!!
Margaret :)
PS. If you want, you can PM me and tell me exactly where your ants are coming in...I'm pretty sure I can tell you how to get rid of them.