How Long Does It Take For Rat Poison To Kill a Rat?

Rats are some of the deadliest pests that give humans a hard time. These troublesome creatures can destroy food and water, and they are also super-spreaders of diseases, such as typhus and bubonic plague. Additionally, rats may destroy your home’s structural damage, forcing you to make untimely repairs or remodeling.

If rats have become a nuisance in your home, you can either use rat traps or rat poison to kill them. However, if the rat infestation is unbearable, poison is the best option as it kills quicker than rat traps. If you’re wondering what time it takes to kill rats using rat poison, you’re in the right place.  

Summary of Contents

How long does it take for rat poison to kill a rat?

The duration takes mouse poison to work depends on a variety of factors. For instance, how well you set up the poison, the size of rats, type of poison, and much more. In this post, we’re going to find out how long it takes for rodent poison to kill a rat and what to do to make the poison even more useful.

Types of rat poison

There are several forms of rat poisons that you should know about. This is because buying the right kind of rat poison will play a role in how quickly it kills rats in your home. Here are the different types of rat poison:

  • Grain bait
  • Rat killer bait
  • Bait blocks

The most common type of rat poison that people usually use is rat bait. This is because baits are highly palatable. Besides, the sweeter the bait, the longer the rats will feed on it. Most mouse poisons feature one of these ingredients; bromadiolone, difenacoum, or brodifacoum. These poisons affect the rat’s blood clotting response, making the rodents suffocate to death.

However, if you have pets at home, being extra safe is very crucial. That’s why we recommend placing rat poison in rat bait stations for added safety.

Things that affect the effectiveness of rat poison

Before we get to how long it takes for rat poison to kill a rat, it’s also crucial to understand other factors that may affect how effective the rat poison functions.

Where do you place the rat poison?

One of the things that you should get right is to position the rat poison correctly. Ensure to put rat position away from bad weather, pets, and kids. Bad weather can dilute your rat poison, and it will become less effective.

On the contrary, putting the bait where pets can access may endanger your pets also. And finally, you should put rat poison away from the reach of your kids. You don’t want the rat baits to get into the hands of your kids.

The best way to ensure the rat bait is useful and not interfered with is by putting it in a rat bait station. Bad weather, kids, and pets won’t reach it. And since rats love familiarity, you won’t have to bother about this. Like other rodents, rats are typically suspicious of anything that seems out of place.

The type of poison

Even though there are various types of rat poison, they can be put into two categories. This includes first-generation rat poison and second-generation rat poison.

First-generation rat poison will slowly kill rats, requiring the rat to feed on the toxin multiple times. An excellent example of 1st generation rat poison is Diphacinone and Warfarin rat poisons.

Second-generation rat poison is much more effective as it kills faster than first-generation poison. Besides, the rat only has to feed once for the toxin to suffocate it. This poison is very lethal, and it usually contains brodifacoum.

If you decide to use 2nd generation rat poison, get rid of the dead rats so that other rats don’t develop bait shyness. The rats will begin to associate the dead rats with the bait. Nonetheless, rats feeding on 1st generation poison will not develop shyness as it takes time to kill.

Do rats have other sources of food aside from the bait?

Find out if rats have other sources of food in the infested building or home. If there is another food source, there is a high chance that the rats will stay away from your bait station. Since rats are habitual feeders, they will likely stay away from a new feeding point if they can still get at their previous feeding points.

Hence, it’s vital to clear out other food sources before setting out rat poison. On top of that, it would help if you get toxins with a smell similar to the food they eat.

Have rats developed a resistance to the bait?

Before you purchase any poison, you should also do some research about the effectiveness of the poison. Some rat poisons have ceased to be useful as rats have developed a resistance for them.

For instance, most first-generation rat poisons have been around for a long. Rat poisons like Warfarin have been around since 1948. Even though this rat poison was effective in the 20th century, it’s not effective in the 21st century. This is because some rat species have developed resistance to the effects of Warfarin.

What period does it take for rat poison to work?

Back to our main question – how long does it take for rat poison to kill a rat? It will depend on the type of rat poison you’re using. If you feed rats the first generation rat poison, it may take five to seven days to suffocate the rat to death. This is because the rat will have to feed multiple times for the impact to be felt.

On the contrary, if you feed rats second-generation rats poison, it will take about two to three days to suffocate them to death. A second-generation poison will cause internal bleeding and make the cat die quicker. Aside from faster death, another advantage of second-generation poison is that other rats that feed on the dead rat will also suffocate to death due to high toxicity. As a result, this method is more effective than using first-generation poison.

However, you shouldn’t worry if your dog or cat ingests the dead rat. The poison won’t have a fatal effect on your pets.

How to make rat poison more effective?

If you have a terrible rat infestation in your home, but they are avoiding the bait, below are a few things that you should carry out to make it more effective:

  • Always clean the bait station and area around the bait station. If there is a dead rat around the bait station, get rid of it. Moreover, it would help if you replaced any bait that has been eaten with fresh ones.
  • Before you set out a bait station, get rid of any other food source. This means that the rats will have no other option but to feed on your bait.
  • Ensure to position the rat poison in an area where they are active. Put bait stations in their path or close to their feeding areas.
  • Feed them the bait a few days before mixing it with poison. Rats are very smart and will nibble the food and move on the next to avoid poisoning. However, if the rat doesn’t fall sick, it will come back for another bite the next.
  • Avoid using rat poison that has been open for over a year. It may not be useful as it was the previous year.


In short, it will take around two to seven days for mouse poison to kill a rat. The speed at which the poison kills a rat will heavily depend on the type of rat poison you use. First-generation rat poison takes many days to work, while second-generation rat poison works within three days. Also, you should consider other factors such as the position of the bait, other sources of food, and resistance from rats.

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