Dog and Fleas

What herb can be given to a Boxer dog to prevent fleas? I also need to protect him from heart disease, we live in MO and this appears to be a problem.

Please see the posting on this site (https://www.richters.com/show.cgi?page=./QandA/Animals/20051109-2.html) entitled, "Cats, Fleas and Pennyroyal". Whilst the article refers to cats, the same information can be used for dogs as well.
As for heart disease, it is difficult to to give you an exact response. There are so many types of heart conditions that it would be best for you to talk with a qualified herbalist who has experience working with dogs. Having said that, a good homemade diet goes a long way for general animal health and a strong circulatory system. Please see the posting "Aging Dog with Arthritis" (https://www.richters.com/show.cgi?page=./QandA/Animals/20051103-2.html) for sources of recipes.