The most effective gopher poisons are single-dose baits containing either strychnine or zinc phosphide, both of which kill pocket gophers after a single feeding. Multi-dose anticoagulant baits also exist but require larger volumes and repeated feedings, making them less practical for most homeowners. Choosing the right poison and placing it correctly underground are the two factors that determine whether you actually solve your gopher problem or just waste time and money.
Types of Gopher Poison
Gopher baits fall into two broad categories: single-dose acute toxicants and multi-dose anticoagulants. The acute options, strychnine and zinc phosphide, have historically been the most effective for pocket gopher control. Anticoagulant baits work by preventing blood from clotting, but they require the gopher to feed multiple times over several days, and you need significantly more bait to get results. For most situations, a single-dose product is the better choice.
Strychnine
Strychnine causes uncontrollable muscle spasms that eventually paralyze breathing. It’s fast-acting and highly toxic to mammals, which is why it carries a “DANGER” label and is classified as a restricted-use pesticide in states like California. In those states, you need a valid pesticide applicator’s license to buy or use it. Where it’s available over the counter, it remains one of the most reliable gopher baits on the market. The downside is that its high toxicity extends to pets, children, and wildlife, so precise underground placement is critical.
Zinc Phosphide
Zinc phosphide works through a different mechanism. When a gopher eats the bait, stomach acid reacts with the compound to release phosphine gas inside the animal’s digestive system. That gas crosses into cells and shuts down energy production, killing cells in the heart, lungs, and liver. If the gopher has food in its stomach, signs of poisoning can begin in less than an hour. On an empty stomach, it can take up to 12 hours.
Zinc phosphide has one notable advantage over strychnine: it carries a much lower risk of secondary poisoning. The compound doesn’t accumulate in a gopher’s muscles or other tissues, so predators and scavengers that eat a dead gopher are generally unaffected. The Michigan Department of Natural Resources recommends zinc phosphide as the rodenticide of choice partly for this reason, though dogs and cats are a possible exception.
Anticoagulant Baits
Products containing chlorophacinone or diphacinone are the main anticoagulant options for gophers. They thin the blood and cause internal bleeding over days. Because gophers need to consume them repeatedly, you have to use much more bait per treatment, and the standard probe method (dropping small amounts into tunnels) doesn’t work as well. These are generally a backup option when acute baits aren’t available or aren’t permitted in your area.
How to Place Bait Underground
Gopher poison only works if it ends up in an active tunnel. Bait left on the surface won’t attract gophers, and it creates a serious hazard for pets, birds, and other animals. The entire goal is to get the poison underground and sealed away.
Start by identifying fresh mounds. Look for dark, moist soil that hasn’t been rained on or dried out. To find the main runway, push a probe into the soil 4 to 10 inches from the base of the mound, on the side closest to the small circular depression you’ll often see. You can also probe between two fresh mounds. When the probe suddenly drops about 2 inches, you’ve hit the tunnel.
Widen the hole by rotating the probe so you can drop bait in. Use two to three pieces if you’re working with vegetable-based bait, or about one level tablespoon of grain bait. Then seal the opening with a plug of grass and cover it with dirt to block out light and air. Gophers avoid open tunnels, so a tight seal keeps them moving through the baited section. Place one bait application for every four to six fresh mounds across your yard.
Risks to Pets and Wildlife
The biggest danger isn’t a dog or cat eating a poisoned gopher. It’s a dog or cat finding exposed bait on the surface or digging into a poorly sealed tunnel. Direct ingestion of strychnine is especially dangerous. In dogs, symptoms appear within 10 minutes to 2 hours and escalate quickly: initial stiffness and nervousness, then a rigid “sawhorse” stance with splayed legs, followed by severe seizures that can be triggered by touch, noise, or bright light. Without treatment, death occurs from respiratory paralysis.
If you suspect your pet has eaten gopher bait, the situation is a veterinary emergency. Strychnine poisoning in particular moves fast, and treatment focuses on stopping seizures, preventing oxygen deprivation, and decontaminating the stomach if the animal isn’t yet showing symptoms. Treatment can last one to three days in severe cases.
Zinc phosphide is somewhat safer from a secondary poisoning standpoint. Experiments exposing predators and scavengers to rodents killed by zinc phosphide found that most species were unaffected. Only dogs and cats showed any signs, and even then, the risk comes mainly from eating a gopher that still has undigested bait in its stomach rather than from the gopher’s body tissue. Still, keeping pets away from treated areas for several days is a smart precaution.
When Trapping Makes More Sense
Poison isn’t always the right tool. If you have dogs that dig, outdoor cats, or small children who play in the yard, mechanical traps eliminate the toxicity risk entirely. Trapping also gives you confirmation that you’ve caught the gopher, something poison can’t always do since gophers may die deep in their burrow system without you ever seeing them.
Traps work best when placed in the main runway using the same probing technique described above. You open the tunnel, set two traps facing opposite directions (since you don’t know which way the gopher will approach), and cover the opening. The trade-off is time. Trapping requires checking and resetting traps daily, while a well-placed bait application can work in a single visit. For large properties or heavy infestations, poison is more practical. For a single gopher tearing up a small yard, a pair of traps is often all you need.
Avoiding Common Mistakes
The most frequent reason gopher poison fails is surface placement. Gophers are fossorial, meaning they live almost entirely underground. Tossing bait near a mound does nothing except put other animals at risk. The bait has to be inside an active tunnel.
Another common mistake is treating old mounds. Gophers constantly dig new tunnels and abandon old ones. If the soil on a mound is dry, pale, or compacted, that section of tunnel is likely inactive. Focus only on fresh, dark mounds with moist soil.
Finally, using too little bait across too few mounds limits your success. A single gopher can maintain a tunnel system spanning several hundred feet. Treating just one or two spots may not intercept the animal. The one-application-per-four-to-six-mounds guideline ensures you’re covering enough of the tunnel network to make contact.