Best rat poison: The most effective methods for dealing with rodent pests

If you’re troubled by scratches in the night, tiny holes in food packaging or droppings around your home, you might be in the market for the best rat poison available. Carrying an array of diseases that can be passed on to humans, including Leptospirosis (Weil’s disease), Salmonella, Listeria, Toxoplasma gondii and Hantavirus, rats are a health risk and can even cause fires by gnawing through electrical cables. 

The list below documents what we consider to be the best rat poisons on the market. Each option has been selected after extensive research and assessments of manufacturer websites, user reviews and data sheets. Our experts analysed key features such as active ingredients, weight, safety concerns and effectiveness, to determine which are the top products to buy. 

If you need more information about the different types of poisons available, as well as a breakdown of the most important things to consider before making a purchase, our buying guide at the bottom of the page has you covered.

Best rat poison: At a glance

The best rat poison to buy in 2024

1. Pest Expert Formula B+ Advanced: Best rapid-acting rat killer

Price when reviewed: £14 | Check price at Amazon

• Pros: Extremely potent, can be used indoors and outside
• Cons: Must be used with a lockable bait box

This is a rat poison that’s designed to get the job done quickly. Pest Expert’s Formula B+ rat poison is four times stronger than other rat poisons containing Bromadiolone and six times stronger than those containing Difenacoum, putting it at the maximum legal strength for pest poison.

Designed to be irresistible to rats, the formulation is made from top-quality whole wheat grain to guarantee immediate appeal, and unlike other rat poisons that rely on multiple feeds, Formula B+ kills on initial ingestion.

Served up in 10x 100g sachets, the strength of Formula B+ means that it mustn’t be left where children or animals can get to it. Don’t be tempted to just scatter it around: it must be used in conjunction with a secure, lockable rat bait box, and crucial that it’s stored well away from inquisitive little fingers (or paws).

Its potency makes it suitable for both indoor and outdoor use, whether that be in homes, factories, farms and restaurants. If fast-acting no-compromise poison is required, Pest Expert Formula B+ is the right choice.

Key specs – Active ingredient: Brodifacoum; Dangerous to humans: Yes; Weight: 1kg

2. Roshield Wax Block Bait Rat & Mouse Killer: Best wax bait rat poison

Price when reviewed: £15 | Check price at Amazon

• Pros: Kills in a single feed, very easy to use
• Cons: Needs to be fully ingested to work

Roshield’s Wax Block Bait is a popular, professional-quality choice for use in lockable bait stations. It uses a formula of culinary-grade wheat flour, blended with chopped wheat, other cereals and proteins, all bound together by edible waxes. This heady blend gives off a unique chocolatey aroma which is apparently impossible for rats to resist.

While that ‘unique chocolatey aroma’ sounds like it might be appealing to young children too, Roshield has added denatonium benzoate, a highly bitter substance, to deter consumption.

The key poisonous ingredient here is Bromadiolone, a powerful anticoagulant that works by stopping the rat’s blood from clotting and, unlike some rat poisons is potent enough to kill from one feed rather than several days of bait station visits.

Roshield’s bait is suitable for domestic and commercial use, and it’s easy to use. Simply secure it in a bait box, place the box alongside walls inside or outside where there is known rat activity, and the rats will inevitably take the bait and return to their nest to die. Job done.

Key specs – Active ingredient: Bromadiolone; Dangerous to humans: Yes; Weight: 600g (2x 300g)

3. The Big Cheese All Weather Block Bait: Best cheap rat poison

Price when reviewed: £8.98 | Check price at Toolstation

• Pros: Cheaper than a lot of the competition
• Cons: Takes up to 10 days to kill

The active ingredient in The Big Cheese’s Block Bait is Difenacoum, a chemical compound that’s been keeping rat populations down since the 70s. Similar to other poisons, this compound is a slow-acting anticoagulant known to attack several major organs as it does its work.

Price is a big selling point: the All Weather Block Bait costs under £10 for 30 blocks. It works with all tamper-proof bait stations and can be used both indoors and outdoors, as the moisture-resistant chemical formula keeps mould and fungi growth at bay while remaining highly palatable to rodents.

It’s not as rapid-acting as Brodifacoum or Bromadiolone – Difenacoum can take up to 10 days to kill rats – but once ingested the process starts immediately, so it’s slow but effective.

It’s still dangerous to both people and pets, so needs to be stored away safely and securely. It’s highly toxic to aquatic life, too, so should be kept clear of ponds and disposed of in an environmentally safe manner.

Key specs – Active ingredients: Difenacoum; Dangerous to humans: Yes; Weight: 300g

4. Elixir Gardens Rodex25: Best grain-based rat poison

Price when reviewed: £13 | Check price at from Amazon

• Pros: Easy for rats to ingest
• Cons: Takes a while to work

Rodex25 is a whole wheat bait formulated with Bromadiolone, and it comes in individual grains rather than little waxy blocks. It also has one other unique element that sets it apart from other options: its colour.

It is hard not to notice Rodex25’s distinctive red hue, which is entirely the point. While with other baits you have to take it on faith that it is being fully ingested, the red dye mixed into the bait can turn rat droppings red, giving an unquestionable indicator that the poison is being eaten without having to actively check.

Arriving in 10x 100g sachets that are easy to dispense into bait boxes, Rodex25’s combination of taste adjuvants and sweeteners helps make it irresistible to rats. Simply set your bait boxes, keep an eye out for red droppings and you’ll know it’s getting to work.

Key specs – Active ingredient: Bromadiolone; Dangerous to humans: Yes; Weight: 1.15kg

5. Ratkil Rat & Mouse Killer – Single Feed: Best cheap Brodifacoum-based rat killer

Price when reviewed: £6.99 | Check price at from Amazon

• Pros: Assures rat elimination from a single feed
• Cons: Fewer pellets in a pack than rivals

If you want the rat-eliminating power of Brodifacoum without spending the premium on Pest Expert Formula B+, then Ratkil is a cheaper option.

Rat poison containing Brodifacoum is the strongest that you are allowed to legally buy in the UK, so you can be assured of rat elimination from a single feed. As with the other baits featured here, Ratkil is made up of a formulation that rats find highly appealing.

Naturally, at this price, you get fewer Brodifacoum-based pellets than you do with other options found here (6x 25g), but this is enough to kill 40 rats, so one bag might just suffice. If you have a more serious infestation, you may want to consider going down the professional exterminator road instead anyway.

As always, a lockable, tamper-proof bait station must be used in conjunction with Ratkil. And, as ever, it’s essential to store any unused bait securely, and well away from children and animals.

Key specs – Active ingredients: Brodifacoum; Dangerous to humans: Yes; Weight: 150g

How to choose the best rat poison

What should I be looking for in a rat poison?

There are different varieties of highly effective chemical poisons legally available in the UK, as well as a selection of physical rat traps, each type mixed into either wax- or grain-based baits, designed to appeal to a rat’s appetite. Some variants kill much more quickly than others but do tend to cost more as a result of their potency.

Whichever you choose, though, they must be used in conjunction with lockable, tamper-proof bait stations (or boxes) to be legal in the UK. It’s essential to keep rat poison well out of reach of people, pets and other wild animals, so don’t be tempted to simply scatter the bait loosely on the ground.

We’ve looked at some of the best examples of each of the most commonly used and professionally recommended types here. All guarantee excellent elimination results, so it comes down to personal choice and budget.

How do I use rat poison with a bait box?

The method is quite simple – secure your poison in the bait station and place it strategically against a wall where rat action is in evidence. It’s important not to clean the area first: rats are intelligent and naturally suspicious of changes to their environment, so a cleaned area will make them wary, not to mention the sudden appearance of bait boxes.

Rats tend to follow set routes, so once you’ve identified these via evidence such as dropping or chewed masonry or wood (a rat’s incisor teeth grow constantly, so they need to gnaw on things to wear their teeth down). They also prefer to move alongside walls for protection, so this is where you set your trap.

Once the rat ingests your poison it will normally return to its nest where it will die. The length of time and number of feeds this takes is dependent on the potency of your poison. With some, it can be up to 10 days, while other poisons can kill within 24 hours.

All the poisons recommended here are anticoagulants that thin the rat’s blood up to the point that the heart can no longer cope with pumping it, leading to a sudden heart attack. Gruesome as that may sound, it is actually a quick, relatively painless death.

Is rat poison dangerous to people?

All rodenticides can be toxic to humans when ingested, and also when inhaled or touched. Avoid contact as much as possible, use gloves when handling it, and always secure away safely from where children and domestic animals might access it. Always take time to read and adhere to the manufacturer’s instructions.

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