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Lily of the Valley Poisoning in Dogs: Signs, Treatment, Prognosis

PawAI Lab
8 min read

Learn how convallatoxin and related cardiac glycosides in lily of the valley can affect a dog's heart, what signs may develop after exposure, and how a veterinarian may manage poisoning.

Quick Answer

Lily of the valley (Convallaria majalis) contains cardiac glycosides, including convallatoxin, that can interfere with the heart's electrical activity and pumping function. Poisoning in dogs may cause drooling, vomiting, diarrhea, weakness, and in serious cases an irregular or slow heartbeat that can become life-threatening. All parts of the plant are considered toxic. There is no safe home treatment. If your dog has eaten lily of the valley, contact a veterinarian or animal poison-control service immediately.

Before using any tool, contact a veterinary professional if your dog may have eaten lily of the valley.

  • US: ASPCA Animal Poison Control (888-426-4435) or Pet Poison Helpline (855-764-7661)
  • UK: Animal PoisonLine (01202 509000) or your nearest veterinary emergency clinic
  • Canada: ASPCA Animal Poison Control (888-426-4435) or Pet Poison Helpline (855-764-7661)
  • AU: Animal Emergency Centre or your regular vet
  • EU: Contact your nearest veterinary emergency service

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Safety Verdict

Toxic. Lily of the valley (Convallaria majalis) contains cardiac glycosides, a group of compounds that includes convallatoxin and related substances. Cardiac glycosides work by affecting the way cells manage sodium and calcium, which in turn influences the electrical signaling and pumping action of the heart. These compounds are similar in action to certain heart medications used in human and veterinary medicine, which is why even small exposures can be significant.

All parts of the plant may be toxic, including the leaves, stems, bell-shaped flowers, and the small red or orange berries that appear later in the season. The water from a vase that held cut lily of the valley may also contain harmful compounds that have leached from the stems. Because toxin concentration can vary and there is no established safe amount for dogs, any known or suspected ingestion should be treated as potentially serious.

What Should the Owner Do Now?

  1. Contact a veterinarian or animal poison-control service immediately. Cardiac effects can develop, so professional guidance is important.
  2. Do not induce vomiting unless a veterinarian or poison-control professional directly instructs you to do so. Improper induction can cause additional harm.
  3. Collect relevant information (see the section below) so the veterinary team can assess the situation accurately.
  4. Do not give food, milk, salt, charcoal, or any home remedy. These are not proven treatments for lily of the valley poisoning and may worsen the situation.
  5. Follow the veterinarian's instructions regarding examination, heart monitoring, or bringing in a sample of the plant for identification.

If your dog has chewed on lily of the valley but you are unsure how much was swallowed, professional consultation is still recommended, because cardiac effects may take time to appear.

What Signs May Occur?

Signs of lily of the valley poisoning in dogs may develop within a few hours of ingestion, though the timeline can vary. Not all signs will appear in every dog, and some dogs show no early symptoms even when effects are developing.

Gastrointestinal Signs

The first signs often involve the digestive system and may include:

  • Drooling or excessive salivation
  • Vomiting
  • Diarrhea
  • Reduced appetite
  • Abdominal discomfort

Cardiac Signs

Because the toxins affect the heart, additional signs may develop that reflect changes in heart rhythm or function:

  • Irregular, slow, or fast heartbeat
  • Weakness or reluctance to move
  • Pale gums
  • Difficulty breathing or rapid breathing
  • Collapse

In severe cases, cardiac glycosides can cause dangerous arrhythmias that may require intensive monitoring and treatment. This is why prompt veterinary care is important, even when a dog initially appears normal.

What Information Should Be Ready?

When you contact a veterinarian or poison-control service, having the following details available can help them assess the situation more efficiently:

  • Dog's details: species, breed, approximate age, and body weight
  • Plant involved: lily of the valley (Convallaria majalis), whether it was a garden plant, cut flowers, or wild specimen
  • Part of plant consumed: leaves, stems, flowers, berries, or water from a vase
  • Estimated amount: best guess of how much was chewed or swallowed
  • Time of ingestion: when the exposure occurred, or the window of time during which it may have happened
  • Current symptoms: any drooling, vomiting, weakness, or breathing changes
  • Plant sample: if available, a photograph or cutting of the plant to help confirm identification
  • Medical history: any pre-existing heart conditions, current medications (especially heart medications), or other health concerns

Provide honest estimates rather than precise numbers. The veterinary team can work with approximate information to determine the best course of action.

Differences That May Affect Risk

Lily of the valley poisoning risk in dogs is influenced by several factors, but none of them allow for a reliable prediction of outcome:

  • Part of plant: Toxin concentration can vary between leaves, flowers, and berries, but all parts are considered potentially hazardous.
  • Amount ingested: Larger ingestions may be more likely to produce severe signs, but individual sensitivity also plays a role.
  • Body size: Smaller dogs may be at greater risk from a given amount of plant material, but toxicity can occur in dogs of any size.
  • Pre-existing conditions: Dogs with existing heart disease may be more vulnerable to the effects of cardiac glycosides.
  • Concurrent medications: Certain medications, particularly those used for heart conditions, can interact with cardiac glycosides and potentially increase risk.

When to Contact a Veterinarian

Contact a veterinarian or animal poison-control service immediately if your dog has eaten or chewed on lily of the valley. Do not wait for symptoms to appear.

Emergency signs that require urgent veterinary attention include:

  • Persistent vomiting or diarrhea
  • Weakness, wobbliness, or collapse
  • Difficulty breathing or changes in breathing pattern
  • Pale gums
  • Irregular, slow, or fast heartbeat

Non-urgent follow-up: If the ingestion occurred hours or days ago and your dog appears normal, a veterinary examination is still recommended to assess for delayed cardiac effects and to confirm that no intervention is needed.

FAQ

How is lily of the valley poisoning in dogs treated?

Treatment depends on the signs present and how much time has passed since ingestion. A veterinarian may provide supportive care such as intravenous fluids, medications to manage heart rhythm, and monitoring of the heart with an electrocardiogram. In some cases, decontamination may be considered if ingestion was recent. Outcomes are generally better when treatment begins before severe cardiac signs develop.

What is the prognosis for lily of the valley poisoning in dogs?

Prognosis can vary based on the amount ingested, the dog's overall health, and how quickly treatment begins. Dogs that receive prompt veterinary care before serious arrhythmias develop often have a better outlook. Because cardiac glycosides can affect the heart, delayed treatment or large ingestions can be more difficult to manage, which is why early contact with a veterinarian is important.

Can a dog recover after eating lily of the valley?

Yes, recovery is possible, particularly with prompt veterinary care. The likelihood of recovery can depend on the amount of plant consumed, the dog's heart health, and how quickly treatment begins. A veterinarian can assess the individual situation and provide guidance on expected outcomes.

Is lily of the valley dangerous to other pets besides dogs?

Yes. Lily of the valley is also considered toxic to cats, and the cardiac glycosides can affect other animals as well. The plant should be kept out of reach of all pets. If any pet may have ingested lily of the valley, contact a veterinarian or animal poison-control service promptly.

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Disclaimer

This article and the PawAI Toxicity Checker provide general safety information and cannot determine an individual pet's toxicity risk or replace a veterinarian or animal poison-control service. If exposure may have occurred, contact an appropriate professional promptly, even if your pet appears well.