Must be from Europe. Cider over here is nonalcoholic. What you would understand to be apple juice. Before the fermantaion process has had a chance to happen. Had a guy from France wondering about the apple cider thing. Here its non alcoholic and I'm right in the middle of apple country. It's great.
But yeah, use regular apple juice. Try to get some that hasn't had all the good stuff filtered out of it. As a general rule if you can see through it its too watered down and too filtered. But even so you can still use it for the flush.