Has anyone tried the plug-in Feliway gizmo for cats?

[eppur_se_muova]

3. It seems to be effective, but not 100%, at preventing urine marking.

The pheromone is apparently a "calming pheromone" produced by mother cats when caring for their young. I would consider it worth a try. The caveat is that coverage is limited; one in the house does not cover every room, but you probably don't need to.

My two adopted ferals remain excitable after nearly 8 years; I think that just never goes away, especially since they moved into a house with two cats already resident -- one who considers herself The Boss, and one who is hostile to contact with the younger female at any time.

Without the vaporizer, we were finding urine marking constantly, so it does have some effect.