Was a "prescription" required/provided? If not, then the tablets you are receiving are probably counterfeit and not tadalafil at all, as tadalafil is available by prescription only. As well, I'm not sure about the United States, but in Canada a generic version of tadalafil is not available, to the best of my knowledge. Here it is only available as Cialis, with the 20mg pills looking like this: http://upload.wikimedia.org/wikipedi...lafil_20mg.jpg

It could contain a whole bunch of harmful ingredients. Personally, I'd be pretty weary taking whatever you've got your hands-on.