I tried it on my clogged kitchen sink. I used one packet first and waited, as per package directions, it didn't do anything. I put the other two packets in, also as per package directions and waited several hours, again, it didn't do anything. I finally had to climb under the sink and undo the plumbing and unstop the drain myself.
DO NOT waste your money on this product. I emailed their customer service because the container clearly states money back guarantee, and as of this writing, they have not responded, so that must be as big a load of hogwash as their product.
Bottom Line: No, I would not recommend this to a friend