No it hasn't done anything bad to my wood floors. I was told it may take the shine off them though but mine aren't really shiny anway, they need another varnish but were like that when we moved in. I just find it does a better cleaning job on hte tiled and lino flooring in my house. I have a large area of wood floor and i find the steam mop is heaps easier to use than a normal mop on those areas.