Lemon eucalyptus oil is a natural treatment that keeps dogs from getting mosquito bites. The New England Journal of Medicine stated in 2002 that the oil provided 120.1 minutes of protection against mosquitoes.
Geranium and soybean oils can also repel mosquitoes. A product called Bite Blocker provides 94.6 minutes of mosquito protection for dogs, according to the New England Journal of Medicine. Citronella is a natural mosquito repellent as well. A University of Guelph study revealed that subjects who were near citronella candles had 42.3 percent less bites from mosquitoes, and subjects who were around citronella incense had 24.2 percent fewer mosquito bites.