she is 7 month old and sometimes chases the cats (not mine-person who i live with) this chasing has only been proper chasing once or twice, all the other times, she just walks next to the cats and sniffs them.  the cats are happy with her becasue they curl up next to her and go to sleep.  however, a litter of kittens is due any day, and the person who i live with, brings them downstairs to mix with the dogs at four weeks old.  because of this, she has told me that i have 4 weeks to stop my dog chasing the cats because they are getting stressed.
I know some dogs have the chasing insticnt in them, especially a working lines pointer and it takes months to train it out of them, and sometimes even then they still chase occaisionally, but she has given me four weeks.  i have no idea what to do, as it is not all the time that she does it. 
any help would be grateful
Sarah

please register so you can let us know what you have tried doing ? have you told her not to do it ? Shes only a puppy once she knows not to chase cats hopefuly it will stay with her . Id teach her a few basic commands ... come . no and stay . first say in a low firm voice no then come ! and stay hopefuly she knows she is wrong and will come to you and of course stay to make sure she dosent run off and do it again . some dogs are cat mad so you would have to find another way if its not working