All natural flea and tick treatments that actually work?

Interesting that this post was revived because one of the neighborhood dogs has just recovered from a very bad reaction to Frontline flea and tick topical. She's a 12 pound doodle, and about a year old. The neighbor had been using Frontline since she was a puppy without a problem, and then a couple of months ago she started developing open sores all over her body. The vet was at a loss as to the cause and sent her to vet determatolgist. It was diagnosed as a reaction to frontline. The problem was even though she stopped putting the frontline on her dog, the sores kept coming. The dog was put on steroids, and my neighbor also changed her diet. The vet even talked to my neighbor about the possibility that the dog may have to be put down because the sores were not healing and they were everywhere. I'm happy to report that several months later the sores have finally cleared. My neighbor was a wreck. I know obviously all dogs don't have reactions to the the poisons in the flea/tick meds, but some can have very serious reactions, and sometimes the reactions don't occur until after using the product for many months or years. It seems to be more prevalent in smaller dogs as well, but any size dog can have a reaction. I am lucky to live in a cooler weather state where we don't have fleas/ticks year-round, but I understand the dilemma for those of you living where fleas and ticks are plentiful and a year round nuisance.