There are many good topical preparations that can be used to kill fleas on a animal. (uvma.org)
The most common are topical preparations applied one time monthly, however, there are other options including injections that last for months and oral medications. (justcatsvet.com)
In addition to dog flea spot on topical preparations, there are also different tablet based products that can help with dogs and fleas. (dog-health-guide.org)