Your cat does not need to eat poison herself to be poisoned by it. The usual route is quieter: a rodent eats bait, staggers out weakened and slow, and becomes easy prey for a hunting cat. Protecting her therefore depends less on anything you can buy and more on knowing where poison is used around her territory, when it is active, and what the people using it are willing to change once they understand what it does beyond rodents.
Talk to neighbours first
Approach neighbours and local businesses as allies before you approach them as a problem. Many people using poison have never considered secondary poisoning, and many will switch to traps or to enclosed bait stations that rodents enter but cats cannot reach into, once someone explains calmly that a poisoned rat does not die neatly in a wall but often dies in the open, in a garden, in front of a cat. Businesses with waste areas and farms with feed stores have real rodent pressure, so arrive with alternatives in mind rather than a demand that they simply stop, and ask what would work for them.
What you need from the conversation is specific: whether poison is in use, where it is placed, what type it is if they know, and when it goes down and comes up. A neighbour who will not change methods may still happily tell you the dates bait is refreshed, and those dates are what your own precautions run on. Keep the relationship warm with updates and thanks, because you will need this conversation again next season, and the neighbour who warns you before each round of baiting is worth more than any fence.
During an active baiting round
During active use around her range, keep her indoors, or let her out only supervised, on a harness or in an enclosed run, until the baiting round and the following days have passed, since dying rodents appear after the bait itself is laid. Shorten the restriction to the real risk window where you can, using the dates your neighbours gave you, because a cat kept in indefinitely for a hazard that lasted a week learns to bolt at doors, and a cat allowed out the day after baiting resumes her hunting exactly when poisoned prey is moving slowly and out in the open.
Sweep her usual hunting corners each morning before she goes out where supervision is the arrangement: check under shrubs, along fence lines and behind sheds for dead or dying rodents, and remove any you find with gloves and a bag, sealed into an outside bin she cannot reach. Removing carcasses is safe ordinary handling of what you find on your own ground; never handle, move or interfere with the poison or bait stations themselves, which are another person's property, a hazard to you and in many places regulated.
Suspected exposure is an emergency
If she may have eaten poison or poisoned prey, or she shows signs a vet would want to assess urgently, such as unusual tiredness, weakness, pale gums, bruising, bleeding, wobbliness or appetite loss, go to an emergency vet now rather than watching her overnight. These signs are possibilities a vet investigates, not a diagnosis you can make at home, and timing matters more than certainty, so do not wait for proof before travelling.
Take information with you: what product was used if you know it, where she may have found it, and when she was last certainly well and when signs began. That note, written on your phone in the car, genuinely helps the vet choose what to test and how to treat, and it is far easier to assemble from your neighbour conversations than from memory in a waiting room. Afterwards, tell the neighbour what happened without blame; a poisoning that reached a vet often changes local practice more than any leaflet. Circle of Love through KinsLe connects local members without charge, which lets one warning about bait on your street travel quickly to other cat owners nearby.