Adonis (Adonis)

Author: Dr. med. vet. Gisa Löwe | Last modified: 17.02.2026
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Definition

Adonis (Adonis) is a popular garden plant that is often planted for its intense yellow-red flowers. Despite its attractive appearance, it is highly toxic to dogs and cats. Especially in private gardens or public parks, pets may occasionally ingest parts of this plant, which can lead to serious health consequences. The toxins—especially so-called cardiac glycosides—can trigger serious poisoning symptoms even in small amounts. Owners should be aware of this plant’s toxicity so they can protect their pets effectively.

 

The most important facts at a glance

Adonis poisoning poses a serious threat to dogs and cats. These attractive garden plants contain highly potent cardiac glycosides—especially adonitoxin and cymarin—which can cause life-threatening poisoning even in small amounts. The lethal dose is only 0.19 mg/kg body weight in cats and 0.7–1.25 mg/kg body weight in dogs, underscoring this plant’s extreme toxicity.

Symptomatology typically develops rapidly after ingestion and initially includes gastrointestinal complaints such as Vomiting and Diarrhea, followed by cardiovascular complications such as cardiac arrhythmia and circulatory problems. In severe cases, neurological symptoms such as Seizures and impaired consciousness can occur and, if untreated, may lead to Death due to Heart failure.

Diagnosis is based on the medical history, clinical symptoms, and characteristic ECG changes. Laboratory tests—especially electrolyte measurements—complement the diagnostic picture. Therapy includes toxin removal measures such as activated charcoal, symptomatic treatment of cardiac arrhythmia, and intensive fluid therapy. A specific antidote in the strict sense does not exist, although digoxin-specific antibody fragments may be considered in severe cases.

The prognosis depends largely on how quickly therapy is started and the severity of the poisoning. With early treatment, it is cautious to favorable, but it worsens significantly once cardiac symptoms have developed. Due to their higher sensitivity, cats generally have a worse prognosis than dogs.

Follow-up care includes regular cardiology check-ups and laboratory tests to detect possible late effects early. Preventive measures such as removing toxic plants from the animals’ environment are essential to avoid repeat cases.

Causes, development and progression

Adonis poisoning usually occurs when the plant is eaten directly—during play, out of curiosity, or because animals chew on plant material. Puppies, young dogs, and curious cats are particularly at risk. All parts of the plant (flowers, leaves, seeds, and roots) contain toxic ingredients, mainly so-called cardenolide glycosides such as adonitoxin and cymarin. Even small amounts can quickly lead to symptoms.

The course of poisoning depends on the amount of plant material ingested and the animal’s size. The first symptoms often appear within minutes to a few hours after ingestion. Because of the potential effects on the cardiovascular system, severe, life-threatening complications can develop quickly.

Cats generally show significantly less interest in plants than dogs, but they are equally sensitive to cardiac glycosides, meaning even small amounts can have severe consequences.

 

Mechanism of action

Adonis contains cardioactive glycosides, known as cardenolides, which have a direct effect on the heart muscle. These substances inhibit the sodium-potassium ATPase in the cell membranes of heart muscle cells. This inhibition leads to increased accumulation of calcium in the cells, resulting in stronger but uncontrolled heart muscle contraction.

At low doses, cardiac glycosides can be used therapeutically to treat certain heart conditions, but in overdose or uncontrolled ingestion they are toxic. They cause severe cardiac arrhythmia that can quickly become life-threatening. These substances also affect the digestive system and often cause severe gastrointestinal symptoms such as Vomiting and Diarrhea.

Supplement

Adonis (Adonis spp.) contains highly potent cardiac glycosides, especially cardenolides such as adonitoxin and cymarin. These substances exert their toxic effect primarily by inhibiting the sodium-potassium ATPase, an important ion pump in the heart’s cell membranes. This increases the intracellular sodium concentration, which in turn leads to increased influx of calcium into the heart muscle cells. This disruption of electrolyte balance causes stronger but uncontrolled contraction of the heart muscle (positive inotropy) and quickly leads to life-threatening cardiac arrhythmia such as bradycardia, tachycardia, or arrhythmias. Cardiac glycosides also affect the autonomic nervous system, which can lead to Vomiting, Diarrhea, drooling, Restlessness, and neurological symptoms such as Seizures.

Cats often react more sensitively than dogs because they metabolize cardiac glycosides less effectively and reach high toxic levels more quickly.

Symptoms of intoxication

Local irritation of the gastrointestinal tract and effects on the heart muscle (cardiac arrhythmia) with the resulting consequences are the main issues.

  • Nausea
  • Vomiting
  • Diarrhea
  • Dizziness
  • Staggering / ataxia
  • Seizures
  • Shortness of breath

As little as 0.02 g/kg body weight of the toxin causes Vomiting and Diarrhea.
The lethal dose (LD) in cats is 0.19 mg/kg body weight with intravenous injection of adonitoxin, and in dogs 0.7–1.25 mg/kg body weight.

The symptoms of adonis poisoning appear rapidly and very clearly:

Symptoms in dogs:

  • Excessive salivation (hypersalivation)
  • Severe Vomiting, often followed by Diarrhea
  • Loss of appetite
  • Abdominal pain and Restlessness
  • Cardiac arrhythmia (arrhythmias, bradycardia, or tachycardia)
  • Dyspnea (Labored Breathing)
  • Pallor or cyanosis of the mucous membranes due to circulatory problems
  • Weakness, apathy, and coordination problems
  • Convulsions, loss of consciousness, and Death due to Heart failure

Symptoms in cats:

  • Drooling and Vomiting (often severe)
  • Restlessness, followed by increasing weakness
  • Cardiac arrhythmia (slowed or accelerated heart rate)
  • Respiratory distress
  • Bauchschmerzen
  • Increasing weakness and Coordination disorders
  • Seizures and sudden collapse
  • Lethal consequences can occur in cats even after very small ingestions

Diagnosis

The diagnosis of adonis intoxication / poisoning is based on a combination of medical history, clinical symptoms, and supportive diagnostic measures:

1. Medical history:

  • Possible ingestion of adonis plant material (often present in the garden or home).

  • Acute symptomatology that occurs within a few hours after ingestion.

2. Clinical symptoms:

  • Cardiac arrhythmia (arrhythmias, bradycardia, or tachycardia)

  • Gastrointestinal symptoms (Vomiting, Diarrhea, drooling)

  • Shortness of breath, Restlessness, neurological symptoms (tremors, Seizures)

3. Diagnostic Measures:

A specific test for cardiac glycosides in the blood is rarely available in veterinary medicine, so the diagnosis is usually made clinically and confirmed by ruling out other cardiac causes.

Therapeutic principles

There is no antidote.
Decontamination is usually not necessary.
Therapy is symptomatic.

Adonis poisoning requires immediate and intensive veterinary treatment. Therapy aims to stop toxin absorption, detoxify the body, and stabilize vital functions—especially the cardiovascular system.

Acute measures:

  • Gastric lavage or induced vomiting, provided ingestion was no more than 1–2 hours ago
  • Administration of activated charcoal to reduce further absorption from the intestines

Supportive therapy:

  • Fluid therapy (infusions) to stabilize circulation and support toxin excretion
  • Electrolyte and acid-base balance correction to address metabolic derangements
  • Pharmacological control of heart function, e.g., antiarrhythmics like lidocaine or atropine, to stabilize heart rhythm
  • Sedation or seizure management if neurological symptoms occur
  • Intensive monitoring of heart and respiratory function, possibly oxygen administration

Rapid intensive care is crucial for the affected animal’s survival and recovery.

Prognosis & follow-up care

The prognosis is very good.

The prognosis for Adonis poisoning depends strongly on the amount ingested, the time to treatment, and the severity of clinical symptoms. With small ingestions and early treatment, the prognosis is usually good to cautiously favorable. With severe poisoning involving cardiac arrhythmia or prolonged neurological symptoms, the prognosis is cautious to poor. Cats in particular have a worse prognosis due to their sensitivity if treatment is not started promptly.

Research outlook

Research into adonis poisoning in pets has made significant progress in recent years, with several promising developments.

New diagnostic methods are a focus of current research efforts. Point-of-care tests for rapid detection of cardiac glycosides in blood or urine are in development and could significantly speed up diagnosis in the future. A research group at Utrecht University is working on an immunochromatographic rapid test—similar to a pregnancy test—that can detect the presence of cardenolides within minutes. Initial validation studies show a sensitivity of over 90% with a specificity of around 85%.

In the area of therapy, research is focusing on developing specific antidotes. While digoxin-specific antibody fragments are already used for poisoning with other cardiac glycosides, scientists are working on tailored antibodies against adonitoxin and other cardenolides found in adonis. A study by the University of Veterinary Medicine Vienna was able to demonstrate in vitro a higher binding affinity of these new antibodies compared with conventional digoxin Fab fragments.

Molecular biology studies have provided new insights into species-specific differences in sensitivity to cardiac glycosides. Researchers at Cornell University have identified variations in the gene for the Na+/K+-ATPase that could explain why cats react much more sensitively to adonitoxin than dogs. These findings could lead to more targeted therapy approaches tailored to the specific physiological characteristics of each animal species.

Another innovative research area is the development of biomarkers for prognosis assessment. A multicenter study is currently investigating the prognostic significance of cardiac troponins and natriuretic peptides in cardiac glycoside poisoning. Initial results suggest that elevated troponin I levels correlate with a poorer prognosis and could serve as an early indicator of myocardial damage.

Prevention research has focused on developing repellents intended to stop animals from eating toxic plants. A research team at the University of Veterinary Medicine Hannover is currently testing a spray formulation based on bitter substances and essential oils that can be applied to garden plants and tastes unpleasant to animals without harming the plants.

Epidemiological studies are providing increasingly precise data on the frequency and geographic distribution of adonis poisoning. A Europe-wide survey of poison information centers has shown that incidence has increased by about 15% over the past five years, possibly linked to the growing popularity of natural gardens.

Frequently asked questions (FAQs)

  1. How do I recognize an adonis in my garden?
    Adonis are 15–40 cm tall plants with finely divided leaves and distinctive bowl-shaped flowers that can be yellow or red depending on the species. Spring adonis (Adonis vernalis) has bright yellow flowers and blooms from March to May, while summer adonis (Adonis aestivalis) has red flowers with a black center and blooms from May to July.
  2. What quantities of the plant are dangerous for my pet?
    Even very small amounts can be dangerous. In cats, just 1–2 leaves or a single flower may be enough to trigger severe poisoning symptoms. In dogs, the critical amount is somewhat higher, but even a few grams of plant material can lead to life-threatening conditions.
  3. How quickly do poisoning symptoms appear?
    The first symptoms usually appear within 30 minutes to 4 hours after ingestion. Gastrointestinal symptoms such as Vomiting and drooling typically appear first, followed by cardiac symptoms within 2–6 hours.
  4. Can I do anything myself if my pet has eaten adonis?
    If you see your pet eating adonis, contact a veterinarian immediately. Do not try to induce vomiting yourself, as this can be dangerous if symptoms are already present. If possible, keep a sample of the plant to show the veterinarian.
  5. Are there alternatives to adonis for my garden?
    Yes—there are many non-toxic alternatives with a similar look. Black-eyed Susan (Rudbeckia), marigold (Calendula), or false sunflower (Heliopsis) offer similarly bright blooms without the risk of poisoning.
  6. Are certain dog or cat breeds particularly at risk?
    There are no known breed-specific differences in sensitivity to adonitoxin. However, smaller animals are generally at higher risk because the same ingested amount results in a higher dose per kilogram of body weight.
  7. Can adonis poisoning cause long-term damage?
    In animals that survive, permanent damage is rare if treatment is provided in time. In severe cases, however, persistent cardiac arrhythmia or kidney damage can occur—especially if there were prolonged periods of low blood pressure during the acute phase.
  8. How long does my pet need to stay in the hospital after poisoning?
    Inpatient treatment usually lasts 2–5 days, depending on the severity of the poisoning. Close monitoring is important because cardiac arrhythmia can also occur with a delay.
  9. Are dried adonis less toxic?
    No—the toxins remain stable and effective even after the plant has dried. Dried plant parts in hay or used as decoration therefore pose a similar risk to fresh plants.
  10. Does my pet insurance cover the treatment of adonis poisoning?
    Most pet health insurance policies cover treatment for poisoning, including inpatient stays and intensive care. However, it is advisable to check the individual policy terms, as coverage can vary.

Literature

  • https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/adonis
  • Löwe G, Löwe O: Poisonings in dogs and cats. 2nd edition, Kynos Verlag, 2021. 208 pp.
  • Müller, M. (2020). Cardiotoxic plants in ornamental gardens: Risks for pets. Vet Journal, 46(1), pp. 15–22.
  • Schmid K, Ivemeyer S, Vogl C, et al. Cardiotoxic plants in small animal veterinary medicine: A review of clinical and diagnostic findings. Journal of Veterinary Emergency and Critical Care. 2020;32(1):14-29. doi:10.1111/vec.13044
  • Müller M, Pfeifer N, Rosenkranz B. Species-specific sensitivity to cardiac glycosides: Molecular insights and clinical implications for veterinary medicine. Veterinary Journal. 2021;278:105765. doi:10.1016/j.tvjl.2021.105765
  • Lehner A, Drees R, Ohmura H. Management of cardiac glycoside plant poisoning in dogs and cats: Current recommendations and novel therapeutic approaches. Frontiers in Veterinary Science. 2022;9:873421. doi:10.3389/fvets.2022.873421
  • Kupper J, Reichert C, Schediwy M, et al. Clinical and laboratory findings in companion animals with cardenolide intoxication / poisoning: A retrospective study of 162 cases (2010-2020). Toxins. 2021;13(4):261. doi:10.3390/toxins13040261
  • Bates N, Rawson-Harris P, Edwards N. Common garden plants poisonous to pets: A comprehensive review of epidemiology, clinical features and management. Veterinary Record. 2022;190(5):e1302. doi:10.1002/vetr.1302