Boric Acid Poisoning in Dogs

Boric acid, a primary ingredient in many natural pest control products, is often touted as safe and nontoxic. Boric acid is considerably safer than synthetic pesticides, but repeated exposure to the substance has shown toxic effects occur in dogs, mice and humans.

Sleepy cross breed dog in basket
Lethargic dog lying on ground
credit: IvonneW/iStock/Getty Images

Getting Into Boric Acid

Boric acid kills insects by drying out their bodies and attacking their nervous systems. Mined from the earth in the form of borate salts, this substance is toxic to animals or humans when ingested or inhaled. Dogs are most likely to contact boric acid when sniffing around areas treated with the powder as an insecticide. Few dogs will readily consume the substance beyond an investigative lick or sniff, though. Ingestion is most likely when the dog licks away powder clinging to his muzzle or paws.

Seeing the Signs

The low toxicity of boric acid makes a few licks relatively harmless to large and medium-size dogs. Toy dogs are at greatest risk for toxic ingestion, with as little as .02 ounce (631 milligrams) of boric acid per pound of body weight creating noticeable toxic effects. Dogs may become thirsty or salivate excessively due to the drying effects of the boric acid. Vomiting and diarrhea of bluish-green matter or blood are usual symptoms. Ingesting large amounts of boric acid can cause skin discoloration, tremors or seizures. Chronic exposure to boric acid results in weight loss, reproductive difficulties, kidney damage and eventual death.

Treating the Poison

If your dog ingests boric acid, take him to the veterinarian. Your vet will examine the dog to determine whether it has caused burns to his esophagus or stomach. Your vet may induce vomiting or pump his stomach to get as much of the substance out of his system as possible. Boric acid is eliminated through the urine and can pose a special danger to dogs suffering from kidney disease. The vet might recommend dialysis to help eliminate the toxin.

Preventing Recurrence

When using boric acid as a pest control method, apply it only in areas your pet can't access, such as behind the refrigerator, in crevices and under furniture. If you need to remove boric acid from a pet-accessible area, don't vacuum it up or disperse it into the air through vigorous sweeping -- you may get ill from inhaling it. Gently wipe it into a dustpan and use a damp cloth to mop up the residue. Lock away all medications, skin lotions and other household items containing boric acid out of your pet's reach.