Our cat's like to open our kitchen cupboards sometimes, what fun! One thing that we have used is the child safety locks, which keeps them out but not always the most practical. Another thing we have tried when they do something that we don't want them to do like get up on the kitchen counters, kitchen table etc., we spray them with a bottle of water. When we spray we tell them down, after a few times of this they know when we pick the spray bottle up and say down that they had better get down or get sprayed. Eventually all we have to do is say down and they listen.