Contrac All-Weather Blox Rodenticide

4.5 out of 5 stars 288 Reviews | 122 Q&A

Contrac All-Weather Blox Rodenticide 18 lbs.

Buy 2 or more: $104.33 each

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Average Rating

4.5 out of 5 stars Rating: 4.6

288 Reviews | 122 Q&A

Product Overview

Contrac All-weather Blox Rodenticide is a multi-edged, single-feeding Rat and Mouse bait. It is formulated with an optimal blend of food-grade ingredients and low wax to yield a highly palatable, weatherable bait that is very attractive to rodents. Secondary poisoning is very minimal with Contrac as an antidote to the poison (vitamin K1) is readily available. We recommend placing the blox in tamper-resistant mouse bait stations or rat bait stations to protect the bait from non-target animals such as dogs and cats.

Note: Due to California state restrictions, this product cannot be sold to California residents.

Features and Specs

Active Ingredient Bromadiolone 0.005%
Target pests Norway Rats, Roof Rats, House Mice, Meadow Voles
For use in Agricultural and Animal Production Facilities, Warehousing and Food Processing Plants, Commercial, Industrial, and Residential accounts
Application Anticoagulant baits are LESS toxic to non-target animals in both primary and secondary poisoning situations than other single-feeding baits
An antidote, Vitamin K1 is readily available and there is a time factor for treatment
Use in Tamper Resistant Bait Stations or areas inaccessible to non-target animals and children.
Change bait every 40-60 days if not eaten to maintain freshness and attractability.
Very cold or warm temperatures will mold or sour the bait faster
Yield Each Blox is 2 in. x 1 in. x 1 in. (28 grams)
Each 4 lb. pail contains approx. 64 blox
Each 18 lb. bucket contains about 288 bloxs
Formulation Professional Product
VT (Restricted To Licensed Applicators Only)
Shelf Life If unopened and sealed, product will last 2-3 years if kept away from extreme temperatures
Once opened, should last a year in normal conditions
Coverage Area All bait placements must be inside or within 50 feet of buildings.
Color Blue
Special Features Multiple edges appeal to a rodent's desire to gnaw, are made with food-grade ingredients and small amounts of paraffin for a highly palatable bait, holds up well, particularly in adverse or moist conditions, superior rodent acceptance and control including control of Warfarin-resistant rats, LESS toxic to non-target animals in both primary and secondary poisoning situations
Time to Kill Single feed, 1-5 days
Shipping Weight 19.14 lbs
Manufacturer Bell Labs (Mfg. Number: CB4047)
EPA Registration 12455-79



Contrac All-weather Blox Rodenticide is a multi-edged, single feeding Rat and Mouse bait. It is formulated with an optimal blend of food grade ingredients and low wax to yield a highly palatable, weatherable bait that is very attractive to rodents. Contrac All-weather Blox contains Bromadiolone, which is less toxic to non-target animals in primary and secondary poisoning.


Baits are small 1 oz. size and can be placed in bait stations, in holes and burrows, or where mice and rats tend to travel. A hole in the center of each block allows it to be placed on bait securing rods in tamper resistant mouse bait stations or rat bait stations, or nail or wire it in place.

Ready-to-use CONTRAC BLOX bait pieces feature a patented multi-edge design that gives rodents plenty of gnawing edges per piece. The 1-oz. bait pieces fit easily into burrows, bait stations and tight baiting places. A hole through the center lets you wire/hang the bait, or place on bait securing rods for added security.

It is colored blue and authorized by USDA for use in federally inspected meat and poultry plants.

Do not place bait in areas where there is a possibility of contaminating food or surfaces that come in direct contact with food. Do not broadcast bait.


Determine areas where rats or mice will most likely find and consume the bait. Generally, these areas are along walls, by gnawed openings, in or beside burrows, in corners and concealed places, between floors and walls, or in locations where rodents or their signs have been seen. Remove as much alternative food as possible.

Norway rats and house mice may consume a lethal dose in one feeding with first dead rodents appearing four to five days after treatment begins.



Each bait block in this container weighs approximately one ounce.

  • RATS: Place 3 to 16 CONTRAC BLOX (usually at intervals of 15 to 30 feet) per placement. Maintain an uninterrupted supply of fresh bait for at least 10 days or until signs of rat activity cease.
  • MICE: Place 1 block per placement. Space placements at 8- to 12- foot intervals. Two CONTRAC BLOX may be needed at points of very high mouse activity. Maintain an uninterrupted supply of fresh bait for at least 15 days or until signs of mouse activity cease.
  • RATS AND MICE: Replace contaminated or spoiled bait immediately. Collect and dispose of all dead animals and leftover bait properly. To prevent reinfestation, limit sources of rodent food, water, and harborage as much as possible. If reinfestation does occur, repeat treatment. Where a continuous source of infestation is present, establish permanent bait stations and replenish as needed.
Review Search   
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  • 5 of 5 Stars

    Mice like it. But...

    By Robert on 02/24/2009

    I live in a row-house and have an on and off again love-hate relationship with mice. They love me. I hate them. I put these Contrac Blox in my detached garage and almost every morning they are nibbled at (there is a field behind the garages). They eat it but is it true that if the bait goes stale you have to throw it out? Does it become ineffective? How long? Is there an expiration date on the pail? I would hate to buy the 18 lb size and then have to throw most of it out. Help?

    Expert ResponseExpert response:
    The fact that the bait is being eaten every day is a good sign. Mice will not die immediately after eating rodenticide baits, and will probably die somewhere out in the field on their way back to the burrow. Contrac lasts about 2 years in the bucket. When placing the bait, the manufacturer recommends that the bait be changed out every 40-60 days.

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    194 of 207 people found this review helpful

  • 5 of 5 Stars

    This stuff is the best!

    By Denis on 05/12/2010

    Verified Purchase

    Living in a restaurant filled neighborhood in DC with unkempt neighbors on both sides of our house led to our backyard becoming a rat highway. It got so bad that we would have 6 or 7 running across every 5 mins. all night - and they were getting closer and closer to the house. We looked at all kinds of new fencing options only to realize it wouldn't have made a difference since they'd probably just burrow underneath it. We bought this and in less than 1 week's time, we have abolished every rat! We only had one meet his maker in the yard that we had to dispose of, the other hundred or so wandered off to die. It's been close a month now and we still have not seen one. This stuff is BAD A@!.

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    146 of 151 people found this review helpful

  • 5 of 5 Stars

    The "TRUTH"

    By Tarik on 03/13/2010

    Verified Purchase

    This stuff is the truth. I've tried the Rex traps and other traps but those other methods just didn't get the job done. I live in a duplex with joining garages and my neighbor had dog food which attracted the rats. They were multiplying faster than I could trap them. I bought Contrac and placed them in stacks of three around my garage also stacked six of them where the garages joined. The next day the six were gone. I replaced the six with six more, they disappeared. Within five days not a sign of rats or droppings. I didn't even have to dispose of the dead rats. This is a winner!!!!!!!!!!!!!!

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    89 of 91 people found this review helpful

  • 5 of 5 Stars

    Mice are gone!

    By Tom on 08/23/2005

    We were getting rundown with field mice from the lot next to our home. Traps were not getting the job done. After 2 weeks using Contrac Blox Rodenticide the mice were gone....Thanx

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    73 of 75 people found this review helpful

  • 5 of 5 Stars

    Best I have seen

    By Harold on 11/09/2006

    This is the best I have seen. I had a bucket of Contrac Blox rodenticide sitting in the barn and the rats ate a hole in the top of the bucket.

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    62 of 67 people found this review helpful

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Questions & Answers

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Is secondary poisoning an issue for cats when using Contrac Blox rodenticide?

We have mice in unfinished areas of our home (garage, basement, and attic) and we have placed bait boxes with Bell's Contrac in these areas. We are not concerned about primary poisoning with our cats since they not allowed in these areas (and the poison is in boxes that the cats could not even fit into). However, my concern is about secondary poisoning. If a mouse somehow made it to a part of the house where the cats are and one of the cats ate the mouse, could it get secondary poisoning from Contrac? I would really appreciate some feedback as I have received mix answers from asking around, including our vet who was not really sure and suggested we contact you all. Thank you!

The risk of secondary poisoning with Contrac Blox is very minimal. A mouse only consumes a very small amount of bait at a time and passes it very quickly only keeping a smaller amount in their liver until they succumb to the effects of the bait. A cat would have to actually eat 20-30 mice that have consumed the bait for it to have an effect. In most cases well fed domesticated animals will not actually eat a mouse or a rat that they come across. Instead they will play with it, chew it and then leave it behind.

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198 of 211 people found this answer helpful

What happens to mice after they eat Contrac Blox?

I live in a mobile home and I purchased Contrac Blox and scattered it under my home. What happens to the mice after they eat it? How long does it take for them to die? Do they need water for this product to work?


Contrac Blox is an anti-coagulant which means once the mice eat this product they begin to bleed to death from the inside.  The mice first become sick, and then grow tired and weak and pass in their sleep.  It can take anywhere from a few hours to a few days depending on how much the mice have eaten.  They do not need water for the product to work.

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147 of 155 people found this answer helpful

What are the new regulations on rodent products that go into effect on June 4th, 2011?
The federal government has decided that certain types of rodenticides should not be sold in the same manner they have been after June 4, 2011.  These regulations were passed to try to prevent over the counter sales of rodenticides to homeowners and minimize secondary poisoning and misuse of rodenticides.  Unfortunately too many people have placed rodenticides in locations they should not be, such as easy to access places that children and pets can easily get to.  Basically all of the smaller quantities of rodent bait that you have been able to purchase over the counter will no longer be available.  You will only be able to purchase bait already inside a rodent station that is a one time use product.  It will come pre-baited in a sealed rodent station.  This will be the general rule for big box stores like Wal-Mart and Home Depot.  For a specialty store like ourselves, Do My Own Pest Control, we will no longer be able to sell certain rodent place packs, liquid rodenticides, or bait blox in smaller quantities than 16 pounds.  This was passed to discourage homeowners from purchasing rodenticides since they have to now purchase them in large quantities.  Most homeowners do not need 16 lbs worth of place packs.  We will be able to continue to sell the current stock that we have of currently labeled product while supplies last.  However, after June 4th, once we sell out of our current stock and start receiving newly manufactured bait, we will no longer be able to sell it in less than 16lb increments.  There will be some baits that we can continue to sell in smaller quantities but they will be very few and only the ones that have a minimal secondary poisoning risk.

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104 of 111 people found this answer helpful

Which rodent bait is best for mice in a house that has two dogs?

I have mice in my house and was wondering which poison is better, Final Blox or Contrac Blox for me? I was reading the info on both and do not really know what the difference is, since they both claim to be the best, which confuses me since they are made by the same company. So my question is which one is best for mice in a house that has two dogs? The bait stations will be placed in areas of the house that the dogs can not get to (attic/basement).

Contrac Blox is usually preferred in homes with pets and/or children as there is a readily available antidote in the event of accidental ingestion and because of the reduced risk of secondary poisonings (if one of your dogs were to eat a poisoned mouse). Final Blox is used when a fast clean out is needed as it will kill the rodents a bit faster than the Contrac Blox. Final Blox does have a higher risk of secondary poisoning. We recommend that you use tamper resistant bait stations that will help stop accidental poisonings of non-target animals no matter which bait you select.

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73 of 84 people found this answer helpful

How do I get rid of slugs that are entering my rodent bait stations and eating the bait?

I have six bait stations with Contrac and notice slugs have really taken to eating the bait. Will it control the slugs too, or am I just losing my bait to them? What should I do to keep slugs out if they are not killed by this?

Contrac bait will not have any effect on insects. We recommend that you sprinkle a slug bait around the exterior of the bait stations to control the slugs before they enter the stations. We have several slug baits available including Hi Yield Snail and Slug Bait, Sluggo Plus Snail & Slug Killer and MotherEarth Granular Scatter Bait.

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58 of 71 people found this answer helpful

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Contrac All-Weather Blox Rodenticide 4.5 out of 5 stars Rating: 4.6 (288 Reviews / 122 Q&A)

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