Pyrethrin is a 100% biodegradable, commonly used pesticide to control mosquitoes, fleas, ticks, and flies and is commonly found in flea and tick preparations used on cats and dogs. Pyrethrin is the natural form of the compound, manufactured from the extract of a specific chrysanthemum plant. The synthetic form is known as pyrethroid. The active ingredient is extracted from the plant by drying and crushing the leaves of the flower or by extracting the oil with the use of a solvent.
The active ingredients in the powder and oil are contact poisons that absorb quickly into the nervous system of the pest paralyzing it. The bug is usually not killed due to the ability of the organism to detoxify itself through the neutralizing effects of enzymes in their body chemistry. To combat this, many pyrethrin manufacturers add other organophosphates or poisons to a product to slow down the enzyme neutralization, making the pyrethrin more effective.
Synthetic compounds, known as pyrethroids, have been produced and are more effective as an insecticide as well as being loss toxic to mammals.
Both natural pyrethrins and synthetic pyrethroids are extremely toxic to aquatic life such as fish and amphibians and should not be used near waterways. Toxicity to birds, whether aquatic or not, is minimal. The toxicity of the compounds is increased as the waters warm in the summer, which coincides with the timeframes of increased use. Toxicity in mammals is low unless exposed to extremely high doses, or if the mammal has an underlying health concern preventing it from being able to process and eliminate the compound. The compounds are not known to be stored in the body as they are easily digestible by the body.
Environmental impacts of the use of pyrethrins are minimal. Plants break down the compound and residual effects are almost non-existent. Pyrethrins are 100% biodegradable, breaking down on their own within months. Crops sprayed with pyrethrins to control pests will have little to no remaining residue by the time they are seen in the marketplace.
Pyrethrins and pyrethroids are commonly used in commercially prepared flea shampoos, sprays, powers, and environmental preparations. It is extremely important to follow the label instructions to avoid potentially harming your pet. Very young cats and dogs as well as aged, or otherwise unhealthy animals should avoid having pyrethrin treatments for pests as they are more likely to develop complications from overdose.