I use frontline on Milo he is 6lb 11oz but, whether you use frontiline or another source of flea protection you must protect your dog. Ticks carry lime disease, nothing you want to mess with also anyone can have fleas a flea disease from someone to someone without there knowledge and bring it into your home. There are a lot of people on the site that use holistic alternatives you might want to do a search on this site for natural flea medication. Here you go I just went to the Search and typed in natural flea this was the first that popped up but there were lots more.
http://www.yorkietalk.com/forums/sho...t=natural+flee
Good Luck