Bromethalin vs. Diphacinone

What's the Difference?

Bromethalin and Diphacinone are both rodenticides commonly used to control rodent populations. However, they differ in their mechanisms of action and potential risks. Bromethalin is a neurotoxin that affects the central nervous system of rodents, causing swelling in the brain and leading to paralysis and death. It is a fast-acting poison, often resulting in death within 24-48 hours after ingestion. On the other hand, Diphacinone is an anticoagulant rodenticide that interferes with blood clotting, causing rodents to bleed internally and eventually die. It is a slower-acting poison, requiring multiple feedings over several days to be effective. While both substances are effective in controlling rodent populations, it is important to handle them with caution and follow proper safety protocols to minimize the risk of accidental exposure to humans and non-target animals.


Chemical FormulaC23H27Br2NO3C23H16O4
Mode of ActionNeurotoxicantAnticoagulant
Target PestsRats and miceRats and mice
FormulationBait blocks or pelletsBait blocks or pellets
UsageIndoor and outdoorIndoor and outdoor
EffectivenessHighly effectiveEffective
Time to Death1-2 days3-7 days

Further Detail


Bromethalin and Diphacinone are two commonly used rodenticides that are effective in controlling rodent populations. While both substances are used for the same purpose, they have distinct attributes that set them apart. In this article, we will explore the characteristics of Bromethalin and Diphacinone, including their mode of action, toxicity, environmental impact, and effectiveness.

Mode of Action

Bromethalin is a neurotoxic rodenticide that acts by disrupting the normal functioning of the rodent's central nervous system. It inhibits the production of adenosine triphosphate (ATP), which is essential for energy production in cells. This disruption leads to the accumulation of sodium ions in nerve cells, causing them to depolarize and ultimately leading to paralysis and death in rodents.

Diphacinone, on the other hand, is an anticoagulant rodenticide. It works by interfering with the synthesis of vitamin K-dependent clotting factors in the liver. Without these clotting factors, rodents experience uncontrolled bleeding, leading to death. Diphacinone is a first-generation anticoagulant, meaning it requires multiple feedings over several days to achieve a lethal effect.


When it comes to toxicity, both Bromethalin and Diphacinone pose risks to non-target animals and humans if not used properly. Bromethalin is highly toxic and can cause acute poisoning in pets, wildlife, and even humans if ingested. It is important to use Bromethalin-based products with caution and follow the recommended application rates to minimize the risk of accidental exposure.

Diphacinone, on the other hand, has a lower acute toxicity compared to Bromethalin. However, it is still considered moderately toxic and can cause poisoning if consumed in large quantities. The delayed action of Diphacinone allows for the possibility of secondary poisoning, where predators or scavengers that feed on poisoned rodents may also be affected.

Environmental Impact

Considering the environmental impact, both Bromethalin and Diphacinone have their own set of concerns. Bromethalin is not known to persist in the environment as it degrades relatively quickly. However, its acute toxicity can pose risks to non-target animals, especially if they consume poisoned rodents. It is crucial to use Bromethalin-based products in a manner that minimizes exposure to non-target species.

Diphacinone, being an anticoagulant, has the potential to accumulate in the food chain. This can lead to secondary poisoning of predators or scavengers that consume poisoned rodents. Additionally, improper disposal of Diphacinone-contaminated carcasses can further contribute to environmental contamination. It is essential to follow proper disposal guidelines to minimize the impact on wildlife and the ecosystem.


Both Bromethalin and Diphacinone are effective in controlling rodent populations, but their modes of action result in different efficacy profiles. Bromethalin acts quickly, often causing death within 24-48 hours after ingestion. This rapid action makes it suitable for situations where immediate control is necessary, such as severe infestations or in sensitive areas where rodents pose a significant threat.

Diphacinone, on the other hand, requires multiple feedings over several days to achieve a lethal effect. This delayed action allows for the poisoned rodents to return to their nests, potentially spreading the bait to other members of the colony. Diphacinone is often used in situations where long-term control is desired, as it provides a sustained effect over time.


In conclusion, Bromethalin and Diphacinone are two rodenticides with distinct attributes. Bromethalin acts as a neurotoxin, disrupting the central nervous system, while Diphacinone is an anticoagulant that interferes with blood clotting. Both substances have their own toxicity risks and environmental concerns, emphasizing the importance of proper usage and disposal. While Bromethalin offers rapid control, Diphacinone provides a sustained effect over time. Ultimately, the choice between these rodenticides depends on the specific situation and the desired outcome in rodent control efforts.

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