Rat poison is not completely illegal in California, but the state has banned most types that were commonly sold to homeowners. Through a series of laws passed between 2020 and 2024, California now restricts seven active ingredients found in popular rodenticide products, leaving only three types legally available for residents to buy and use on their own.
What’s Banned and What’s Still Legal
California residents and unlicensed pest control operators cannot use rodenticides containing any of these active ingredients:
- Brodifacoum
- Bromadiolone
- Difethialone
- Chlorophacinone
- Diphacinone
- Strychnine
- Warfarin
If you’ve used rat poison in the past, there’s a good chance it contained one of these ingredients. The first four on the list are anticoagulant rodenticides, which work by preventing blood from clotting. They were the most widely sold consumer products for years. The remaining three were restricted through additional legislation or existing state regulations.
The toxic bait options still available for California residents are bromethalin, cholecalciferol (a form of vitamin D3), and zinc phosphide. These work through different mechanisms than the banned anticoagulants. Bromethalin and cholecalciferol can only be used to control rats and mice, not other rodents like gophers or ground squirrels. Zinc phosphide has broader labeling for burrowing rodents.
How California Got Here
The restrictions rolled out in stages. Assembly Bill 1788, called the California Ecosystems Protection Act, was signed by Governor Newsom in 2020 and banned the four second-generation anticoagulant rodenticides: brodifacoum, bromadiolone, difenacoum, and difethialone. These are the most potent blood-thinning poisons and the ones most dangerous to wildlife.
Then in 2023, AB 1322 added diphacinone to the restricted list, effective January 1, 2024. Diphacinone is a first-generation anticoagulant that had remained available after the initial ban. Under the new law, most uses of diphacinone are prohibited statewide, and any remaining products must be sold through licensed dealers.
The most recent law, Assembly Bill 2552 (the Poison-Free Wildlife Act), further tightened what’s available to consumers. Today, the majority of rodenticide products on the market can only be used by licensed pest control professionals who must follow specific guidelines to minimize harm to wildlife.
Why California Banned These Products
The driving force behind these laws was wildlife poisoning. Anticoagulant rodenticides don’t just kill the rat that eats them. The poison stays in the animal’s body for days or weeks, and any predator that eats the dying or dead rodent gets a dose too. This is called secondary poisoning, and it has been devastating to California’s wildlife.
Studies found that 96 percent of mountain lions that were necropsied showed exposure to anticoagulant rodenticides. More than 80 percent of raptors studied, including hawks, eagles, and owls, tested positive as well. The exposure doesn’t always kill these animals outright, but it causes chronic problems with growth and reproduction that weaken populations over time. Bobcats, coyotes, foxes, and endangered species like the San Joaquin kit fox and the Pacific fisher were also affected.
What Licensed Professionals Can Still Use
The bans apply primarily to consumer use. Licensed pest control professionals in California can still use restricted rodenticides, but they must follow strict guidelines designed to reduce wildlife exposure. This includes using tamper-resistant bait stations, monitoring bait regularly, and documenting use. The idea is that trained applicators are better equipped to minimize the amount of poison entering the broader ecosystem.
If you have a serious rodent problem that the three legal consumer products can’t handle, hiring a licensed professional is the route California law pushes you toward.
Buying Rat Poison Online
One important caution: California’s restrictions don’t automatically prevent online retailers from shipping banned products to your address. UC Agriculture and Natural Resources specifically warns residents to use caution when purchasing rodenticides online to avoid accidentally buying restricted materials. If you order a product containing brodifacoum or diphacinone from an out-of-state seller, possessing and using it in California still violates state law. Always check the active ingredient on the label before purchasing.
Non-Chemical Options for Rodent Control
Given how limited chemical options have become for California homeowners, many pest management experts now emphasize non-toxic approaches as a first line of defense. Snap traps remain fully legal and effective for rats and mice when placed correctly. Electronic traps that deliver a lethal shock are another option. Exclusion, meaning sealing gaps and entry points in your home’s exterior, is the single most effective long-term strategy because it stops the problem at its source rather than killing rodents after they’ve already moved in.
Removing outdoor food sources matters too. Bird feeders, pet food left outside, fallen fruit, and open compost bins all attract rodents. Combining exclusion with habitat modification often eliminates the need for any poison at all, which is part of what California’s legislation is designed to encourage.