Instructions
Spray the cat with water from a spray bottle on its torso or rear end (never in the face) whenever the cat walks through the door or tries to open it from the other side.
Place strips of double-sided tape in the area where the cat pushes on the door -- cats hate sticky surfaces. Replace the tape when it loses its effectiveness; remove it once the behavior has stopped.
Spray the door and the area around the door with an even mixture of water and citrus juice, such as lemon juice or orange juice, as cat do not like the smell of citrus. Clean the area around the door, and respray as necessary.
How to Keep Cats From Opening Doors
The independence that a cat displays is both a treasured behavior and a challenge to its owner at times. A cat's natural curiosity can lead it into forbidden areas, such as the garage, a baby's nursery or outdoors. By making the act of opening a door an unpleasant experience for your kitty, you will eventually encourage it to refrain from that behavior.