Imidacloprid (often sold as Advantage)

Imidacloprid is toxic to animal nervous systems. In a test conducted by an imidacloprid manufacturer, it caused tremors in laboratory animals.

For more information about this study, click here and look under acute neurotoxicity.

Scientists from the Chinese Academy of Sciences showed that imidacloprid causes damage to DNA (the genetic material in living cells) in laboratory tests with human blood cells.

To see an abstract of this study, click here.

In a test conducted by an imidacloprid manufacturer, pregnancy loss (miscarriage) was more common in laboratory animals exposed to imidacloprid than in unexposed animals.

For more information about this study, click here and look under reproductive toxicity and rabbits.

Fipronil (often sold as Frontline)

Fipronil insecticide products disrupt hormone function. Scientists at the Universidade Federal do Parana in Brazil showed that an application of Frontline to laboratory animals caused dramatic changes in the levels of two sex hormones and disrupted the animals' reproductive cycle.

To see an abstract of this study, click here.

The U.S. Environmental Protection Agency (EPA) classifies fipronil as a carcinogen (a chemical that can cause cancer).

To see the list of pesticides that have classified by EPA for their ability to cause cancer, click here.

Fipronil insecticides are persistent. Researchers at Murray State University showed Frontline persists for at least 56 days on pets' skin.

To see an abstract of this study, click here.

To see NCAP's detailed information about the hazards of imidacloprid and fipronil, click here.