Dog Herbicide Poisoning: Symptoms, Emergency Response, Dangerous Dosages, and Prevention – A Complete Guide

Emergency/ToxicityDiseasesMeongsiljang Veterinary Advisory Board

We’ve compiled a comprehensive guide covering the signs of poisoning in dogs that lick or ingest herbicides, immediate emergency steps to take, the varying levels of danger associated with different types of herbicides, and tips for preventing future incidents.

What Is Dog Herbicide Poisoning?

Dog herbicide poisoning occurs when ingredients from herbicides used to remove weeds enter a dog’s body, primarily causing irritation to the digestive tract, eyes, and skin. According to veterinary toxicology textbooks, household and lawn herbicides generally pose a low toxicity risk to animals, with symptoms typically being mild and often resolving on their own within 24 to 48 hours. However, undiluted concentrates or products mixed with insecticides or fungicides may have higher toxicity. Therefore, if you suspect your dog has licked or ingested herbicide, it is important to monitor their condition closely and check the product’s ingredients, even if no symptoms are present. If you suspect exposure to concentrated solutions or highly toxic ingredients (such as paraquat), or if symptoms appear, contact a veterinary clinic immediately for safe evaluation and treatment.

Routes of Herbicide Exposure and Key Ingredients

There are three main ways dogs can be exposed to herbicides.

Direct ingestion: Licking or chewing grass or weeds that have been sprayed with herbicide.

Skin contact: Walking through treated areas and then licking their paws, or having direct skin contact with the residue.

Inhalation: Breathing in spray mist or powder particles shortly after application.

However, according to veterinary textbooks, exposure to grass after spraying is rarely enough to cause poisoning. The greater risk comes from exposure to the concentrated, undiluted product. Glyphosate-based herbicides, commonly used in Korea, primarily cause gastrointestinal and eye irritation. This is reportedly due to the surfactants included in the formulation rather than the herbicidal active ingredient itself. In contrast, paraquat and diquat are classified as highly toxic substances in veterinary literature. If exposure to these is suspected, immediate veterinary evaluation is essential.

Checklist of Main Symptoms of Dog Herbicide Poisoning

Vomiting: This is often the first sign to appear, typically within a few hours of exposure.

Diarrhea or black/tarry stools (melena): Gastrointestinal irritation may cause loose stools or black, blood-tinged feces.

Lethargy and ataxia: Your pet may seem weak and reluctant to move, or show signs of unsteadiness (ataxia) or hindlimb weakness.

Eye and skin irritation: Symptoms may include excessive tearing, conjunctivitis, or skin redness.

Nasal and respiratory irritation: Inhalation of dust or spray can irritate the nose and upper airways.

Muscle symptoms: In the case of 2,4-D-based herbicides, muscle issues such as myotonia (muscle stiffness) have been reported.

Most symptoms from household herbicides are mild and resolve on their own within 24–48 hours. However, if symptoms are severe—such as seizures or profound lethargy—or persist, immediate veterinary care is necessary.

A lethargic puppy lying on the examination table at the animal hospital

Go to an Emergency Hospital Immediately If You See These Symptoms

If you notice any of the symptoms below or suspect exposure to a highly toxic herbicide, take your pet to a 24-hour emergency animal hospital immediately. In particular, paraquat and diquat are highly toxic compounds specifically highlighted in veterinary textbooks, so prompt veterinary care is crucial if exposure is suspected. • If seizures or convulsions have occurred one or more times • If your pet appears disoriented or is unable to stand on its own • If there is blood in the stool or urine • If your pet is breathing rapidly or appears to be struggling to breathe • If the ingested product contains highly toxic ingredients such as paraquat or diquat, or if it is an undiluted concentrate or a mixed pesticide product

Emergency Steps Owners Can Take Before Going to the Vet

Step 1: Keep the herbicide container and label handy. Having the ingredient name allows the veterinarian to quickly determine the appropriate treatment plan. Step 2: Wash the paws and fur. If your pet walked through the sprayed area, rinse their paw pads immediately with lukewarm water. Step 3: Do not induce vomiting. If the herbicide contains corrosive ingredients, vomiting can cause further damage to the esophagus. Do not attempt to induce vomiting on your own. Step 4: Offer only small amounts of water. It is okay to let your pet drink a little water, but do not give them milk or food. Please recall and inform the veterinarian of the time of ingestion, the amount ingested, and the type of herbicide as accurately as possible.

Diagnosis and Treatment at the Veterinary Hospital

The veterinarian will determine the treatment plan based on the type of herbicide ingested and the symptoms presented.

Inducing vomiting and gastric lavage: If symptoms are absent and a relatively short time has passed since ingestion, procedures to empty the toxins from the stomach may be considered.

Activated charcoal administration: Activated charcoal may be administered to reduce toxin absorption.

Intravenous fluid therapy: IV fluids may be used to correct dehydration, protect kidney function, and aid in toxin elimination.

Blood and urine tests: These tests check liver and kidney function, as well as blood cell counts, to assess the extent of organ damage.

However, most herbicide poisonings are managed with supportive and symptomatic care, as there is no specific antidote. In particular, household herbicides tend to cause relatively mild symptoms, and pets often recover with minimal supportive treatment, generally resulting in a favorable prognosis.

A puppy receiving intravenous fluid therapy at the animal hospital

Risk Levels and Prognosis by Herbicide Type

The level of risk and the potential for recovery vary depending on the active ingredients in the herbicide. Glyphosate-based products (e.g., Roundup): Exposure is common, but actual poisoning is rare, and the prognosis is generally favorable with low-level exposure. Symptoms primarily involve the gastrointestinal tract, such as vomiting and diarrhea.

2,4-D-based products: In addition to vomiting and diarrhea, neurological and muscular symptoms have been reported, including lethargy, ataxia (loss of coordination), hindlimb weakness, and abnormal muscle tone. However, poisoning from mere exposure to treated grass is uncommon.

Paraquat and diquat-based products: These are highly toxic ingredients often covered in dedicated sections of veterinary textbooks. If exposure is suspected, prompt veterinary care is critical.

Bringing the herbicide container to the clinic, with the ingredient list visible, will greatly assist your veterinarian in making an accurate assessment.

Extra Caution for Small Breeds, Senior Dogs, and Dogs with Underlying Conditions

Smaller dogs are more susceptible to the effects of the same amount of toxin due to their lighter body weight. Senior dogs with reduced liver or kidney function, or those with underlying health conditions, may experience a rapid worsening of symptoms. Owners of small breeds such as Maltese, Pomeranians, and Miniature Schnauzers should thoroughly wash their dog's paws if they have walked through areas where herbicides have been sprayed.

How to Prevent Herbicide Poisoning During Walks

Check for pesticide-sprayed areas: Avoid zones in parks or apartment complexes marked with "Pesticide Spraying in Progress" signs. As a general guideline, keep your dog out of these areas for at least 24 to 48 hours after spraying, or until the chemicals have completely dried.

Wash paws after walks: Make it a habit to gently wipe your dog’s paw pads with lukewarm water after returning home.

Discourage grass licking: If your dog tries to lick grass or weeds, gently redirect them to another area right away.

Store concentrated pesticide safely: Undiluted pesticide concentrates are more toxic, so keep them out of your dog’s reach. Also, prevent your dog from accessing areas where pesticides are mixed or stored.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

My dog licked a small amount of herbicide but isn't showing any symptoms. Should I just leave it alone?

Household and lawn herbicides generally pose a low toxicity risk, and poisoning from mere contact with treated grass is rare. However, depending on the product, symptoms may appear several hours after exposure. Exercise extra caution with paraquat and diquat-based products, undiluted concentrated solutions, and herbicide-insecticide mixtures. We recommend closely monitoring your pet for any symptoms and bringing the herbicide container to your veterinarian for guidance.

Should I induce vomiting at home?

We do not recommend inducing vomiting without veterinary guidance. If the ingested substance contains corrosive ingredients, vomiting can cause further damage to the esophagus and oral mucosa. It is best to rinse your pet’s paws, bring the container of the substance, and head to the clinic immediately.

How many days should I wait after herbicide application before it’s safe to walk my dog?

For safety, keep pets away from the treated area for at least 24 to 48 hours after application, or until the herbicide has completely dried. Since drying times can vary depending on weather conditions and the specific product used, please strictly follow any waiting periods indicated on the warning signs.

Will giving milk help if my dog ingests weed killer?

There is no evidence that milk helps with herbicide toxicity. In fact, feeding your pet can make it harder to induce vomiting or perform a stomach flush once you arrive at the clinic. Allow only small amounts of water and head to the vet immediately.

How long does it take to recover after treatment?

Glyphosate-based and other common household herbicides typically cause mild symptoms that usually resolve on their own within 24 to 48 hours, with a generally favorable prognosis. However, highly toxic ingredients such as those in the paraquat and diquat families require specific medical treatment and may have different outcomes, so please be sure to consult your veterinarian for a detailed explanation of your pet's condition.

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References

[1] Osweiler GD et al., Blackwell's Five-Minute Veterinary Consult Clinical Companion: Small Animal Toxicology, 3rd Ed., Wiley-Blackwell, 2011

[2] Schaer M et al., Clinical Medicine of the Dog and Cat, 4th Ed., CRC Press, 2022

[3] Plumb DC, Plumb's Veterinary Drug Handbook, 10th Ed., Wiley-Blackwell, 2023

[4] Costello MF et al., Feline Emergency and Critical Care Medicine, 2nd Ed., Wiley-Blackwell, 2013