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Is Lily of the Valley Toxic to Dogs? Cardiac Glycoside Risks

PawAI Lab
8 min read

Learn why lily of the valley is considered toxic to dogs, how its cardiac glycosides can affect the heart, what signs may develop after exposure, and the steps a veterinarian may recommend.

Quick Answer

Yes, lily of the valley (Convallaria majalis) is toxic to dogs. The plant contains cardiac glycosides, including convallatoxin, which can affect how the heart functions. Signs may include vomiting, diarrhea, weakness, and in serious cases an irregular or slow heartbeat. All parts of the plant, including the flowers, leaves, and berries, may be toxic. 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 can affect the electrical activity and pumping action of the heart by influencing how cells manage sodium and calcium. 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. Even the water from a vase that held cut lily of the valley may contain harmful compounds. 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.

Early signs may include:

  • Drooling or excessive salivation
  • Vomiting or diarrhea
  • Reduced appetite
  • Lethargy or weakness

As cardiac effects develop, additional signs may appear:

  • Irregular, slow, or fast heartbeat
  • Weakness or collapse
  • Pale gums
  • Difficulty breathing or rapid breathing
  • In severe cases, seizures

Because cardiac glycosides can affect the heart's rhythm, serious cases may involve dangerous arrhythmias that require intensive monitoring. 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 toxicity 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 or those taking heart medications may be more vulnerable to the effects of cardiac glycosides.
  • Concurrent medications: Certain medications can interact with cardiac glycosides, potentially increasing risk.

Because of these uncertainties, any known or suspected ingestion should be treated as potentially serious, regardless of the dog's size or the amount involved.

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

Is lily of the valley as dangerous as true lilies to dogs?

Lily of the valley is toxic to dogs, but it is a different plant from true lilies (Lilium and Hemerocallis species). True lilies are especially dangerous to cats, while lily of the valley affects the heart through cardiac glycosides and can be hazardous to both dogs and cats. Both warrant immediate veterinary contact if ingested.

Can lily of the valley poisoning in dogs be treated?

Yes, with prompt veterinary care. A veterinarian may provide supportive care such as intravenous fluids, medications to manage heart rhythm, and monitoring of the heart with an electrocardiogram. Outcomes are generally better when treatment begins before severe cardiac signs develop.

Are the berries of lily of the valley dangerous to dogs?

Yes. The berries of lily of the valley are considered toxic, as are the leaves, stems, and flowers. Dogs that chew or swallow any part of the plant should be evaluated by a veterinarian.

What if my dog drank water from a vase of lily of the valley?

The water from a vase holding lily of the valley may contain cardiac glycosides that have leached from the stems and flowers. If your dog has drunk this water, contact a veterinarian or animal poison-control service for guidance, even if your dog seems well.

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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.