Are Larkspur Plants Toxic to Dogs? Symptoms and Care

Last updated: April 9, 2026

Yes, Larkspur Is Highly Toxic to Dogs

Larkspur is highly toxic to dogs, and ingestion of any part of the plant should be treated as a serious medical emergency. This popular garden ornamental, loved for its tall spires of blue, purple, pink, or white flowers, contains potent alkaloids that affect the cardiovascular and nervous systems. Even small amounts can cause trembling, weakness, collapse, and in severe cases, death from cardiac or respiratory failure. Larkspur is particularly dangerous because dogs do not need to eat large quantities to become seriously ill.

Larkspur (Delphinium species and its close relatives) grows in cottage gardens, wildflower meadows, and decorative plantings throughout much of North America. The plant is related to monkshood and other highly toxic members of the buttercup family. Every part of larkspur is poisonous, but young plants and seeds contain the highest concentrations of the toxic alkaloids.

Severity rating: Severe. Larkspur ingestion is a veterinary emergency, with potentially fatal cardiovascular and neurological effects.

The Toxic Compounds in Larkspur

Larkspur’s toxicity comes from a group of diterpenoid alkaloids, including methyllycaconitine, delphinine, and related compounds. These alkaloids work by blocking nicotinic acetylcholine receptors at neuromuscular junctions, which interferes with the normal signals between nerves and muscles. The result is weakness, paralysis, and, in severe cases, cardiac arrhythmia and respiratory failure.

Toxicity varies with several factors:

• Plant age: Young plants and new growth contain the highest alkaloid concentrations.
• Plant part: Seeds are generally the most toxic, followed by leaves and stems. Flowers are also dangerous.
• Species: Different larkspur species contain varying alkaloid profiles and potencies.
• Growing conditions: Plants grown in certain soils or under stress may have higher toxin levels.

This variability means even experienced gardeners cannot reliably judge how dangerous a particular larkspur plant is. The safest assumption is that all parts of all larkspur species are severely toxic to dogs.

Clinical Symptoms of Larkspur Poisoning

Symptoms typically develop within a few hours of ingestion and can progress rapidly. Early signs include:

• Excessive drooling
• Vomiting
• Diarrhea
• Abdominal pain
• Loss of appetite
• Lethargy
• Weakness
• Stiff or wobbly gait

As toxicity progresses, more severe neurological and cardiovascular symptoms can develop:

• Muscle tremors and twitching
• Difficulty standing or walking
• Collapse
• Weak or irregular pulse
• Slow or erratic heart rate
• Low blood pressure
• Difficulty breathing
• Convulsions
• Cardiac arrest
• Respiratory failure

Death can occur within hours of symptom onset in severe cases, making fast veterinary intervention critical. Do not wait to see how symptoms progress, and do not assume mild early signs mean a mild case.

What to Do If Your Dog Ate Larkspur

Larkspur exposure is an emergency. Act immediately:

1. Remove any remaining plant material from your dog’s mouth and surrounding area.
2. Collect a sample of the plant if you are unsure of identification, including flowers, leaves, and any seed pods.
3. Call your veterinarian or nearest emergency animal hospital immediately. Do not wait for symptoms to develop.
4. Call the ASPCA Animal Poison Control Center at 888-426-4435 or the Pet Poison Helpline at 855-764-7661 for 24/7 guidance on the way to the clinic.
5. Do not induce vomiting at home. With cardiac toxins, vomiting can worsen instability.
6. Transport your dog carefully, keeping them calm and warm.

Bring the plant sample or a clear photo to the clinic. Correct identification helps the veterinary team choose the right treatment approach and monitoring plan.

Veterinary Treatment for Larkspur Toxicity

Treatment is aggressive and supportive. Depending on how symptomatic your dog is, care may include:

• Induced vomiting under veterinary supervision if ingestion was recent and the dog is stable
• Gastric lavage (stomach pumping) in severe recent ingestions
• Activated charcoal to bind remaining toxins in the gut
• IV fluids to support circulation and flush toxins
• Cardiac monitoring with ECG to detect arrhythmias
• Antiarrhythmic medications as needed
• Respiratory support, including oxygen or mechanical ventilation in severe cases
• Anticonvulsants for seizures
• Atropine or other medications to counter specific cardiovascular effects
• Intensive care hospitalization for monitoring over 24 to 72 hours

There is no specific antidote for larkspur alkaloids, which is why supportive care focused on cardiac and respiratory stability is the mainstay of treatment. Recovery depends on how much was eaten, how quickly treatment began, and the dog’s overall health.

Preventing Larkspur Exposure

The best protection is avoiding larkspur entirely in dog households. If you already have it in your yard, consider these steps:

• Remove all larkspur plants and dispose of them where dogs cannot access them
• Replace with dog-safe alternatives like snapdragons, sunflowers, zinnias, or marigolds (in small amounts)
• Fence off any areas where larkspur has naturalized and cannot be fully removed
• Watch for volunteer seedlings the following year, as seeds can persist in the soil
• Check bouquets and cut flower arrangements for larkspur before bringing them indoors
• Train a reliable “leave it” command for walks in areas where larkspur grows wild

Larkspur is closely related to several other toxic garden plants. Our guides on delphinium and cats, monkshood and cats, and columbine and dogs cover more plants in the buttercup family to watch for.

Call the Vet Immediately

Any suspected larkspur ingestion requires immediate veterinary attention. Do not wait if your dog:

• Ate or may have eaten any part of a larkspur plant
• Is drooling, vomiting, or has diarrhea after being in a garden with larkspur
• Is weak, wobbly, or collapsing
• Has tremors or seizures
• Is breathing irregularly or having difficulty breathing
• Has an irregular pulse or slow heart rate
• Is a puppy, small breed, or has heart problems

Call your vet, an emergency clinic, and the ASPCA Animal Poison Control Center (888-426-4435) or Pet Poison Helpline (855-764-7661) as soon as possible. These services can coordinate with your vet in real time to guide treatment decisions.

Frequently Asked Questions

How much larkspur is fatal to a dog?

Even small amounts can be fatal, especially for small dogs. In livestock studies, as little as 0.5% of body weight in plant material has proven lethal to cattle. Treat any ingestion as potentially life-threatening.

What is the difference between larkspur and delphinium?

The terms are often used interchangeably. Botanically, true larkspur usually refers to annual species (Consolida) while delphinium refers to perennials. Both contain similar toxic alkaloids and are equally dangerous.

Are larkspur seeds more toxic than leaves?

Yes. Seeds contain some of the highest alkaloid concentrations in the plant and are a particular risk if your dog digs up seed packets or eats them from garden beds.

Does drying or cooking reduce larkspur toxicity?

No. Drying does not significantly reduce alkaloid content, and cooking is not relevant since no one intentionally feeds larkspur. Dried larkspur flowers used in crafts or bouquets are still toxic.

Can my dog be exposed to larkspur through water or pollen?

Direct ingestion of plant material is the main risk. Pollen and trace contamination from flower water are not typically toxic, though water from a vase holding fresh larkspur should be kept away from pets. For more plant dangers, see our guide on bleeding heart and dogs.