Rotate based off of a mouse.

First of all, I know there are a lot of questions with this on it and I thought I knew how to do it (when I looked it up, it was saying almost the same thing as what I was doing) but none of them worked even the answered ones. My code is in the update loop:

         transform.rotation = new Quaternion(transform.rotation.x, transform.rotation.y+Input.GetAxis ("Mouse Y")*10, transform.rotation.z, transform.rotation.w);
         target.transform.rotation = new Quaternion(target.transform.rotation.x, target.transform.rotation.y+Input.GetAxis ("Mouse Y")*10, target.transform.rotation.z, target.transform.rotation.w);

(Im rotating two objects and target is the other one)