Spurge Species (Euphorbia Spp.)
Spurge plants (Euphorbiaceae) represent an extensive plant family with over 2000 species, distributed worldwide. Characteristic of these plants is the milky, white sap that exudes when the plant is injured and contains various toxic substances. Among the best-known representatives in households and gardens are the poinsettia (Euphorbia pulcherrima), the crown of thorns (Euphorbia milii), croton (Codiaeum variegatum), as well as various native spurge species in gardens and meadows.
The toxicological relevance of these plants for pets arises from the terpenes they contain, especially triterpene saponins and diterpene esters, which can have a strong irritating effect on skin and mucous membranes. The degree of toxicity varies considerably between different species, with some species like the poinsettia being less toxic than previously assumed, while other species like the Caper Spurge (Euphorbia lathyris) can cause significantly stronger poisoning symptoms.
Poisonings in pets are relatively rare because the sharp, bitter taste of the milky sap usually deters dogs and cats. Nevertheless, especially young, curious animals or those with pica behavior can be affected.
The most important facts at a glance
Poisoning by spurge species represents a relevant toxicological risk for dogs and cats, although it occurs relatively rarely due to the deterrent taste of the milky sap. The toxic active ingredients, mainly various terpene compounds, can cause different symptom complexes depending on the route of exposure.
Skin contact leads to local irritation with redness and swelling, while eye contact can cause potentially severe corneal damage. Oral ingestion leads to irritation of the oral mucous membrane, salivation, vomiting, and diarrhea. In severe cases, neurological symptoms and cardiovascular impairment may also occur.
Diagnosis is primarily based on the animal’s history and clinical picture, with identification of the responsible plant being helpful. Therapy is symptomatic and includes decontamination measures, supportive fluid therapy, and treatment of specific symptoms, depending on the route of exposure.
The prognosis is generally good with timely and adequate treatment, although eye injuries in particular carry an increased risk of permanent damage. Preventive measures such as removing toxic plants from the pet’s environment are the most effective protection against poisoning.
Pet owners should be informed about the potential dangers of spurge plants and seek veterinary help immediately if poisoning is suspected. Early detection and treatment are crucial for a favorable outcome.
Causes, development and progression
The toxic active ingredients are various terpenes (triterpene saponins, diterpene esters) that can irritate the skin, the mucous membranes of the gastrointestinal tract, and the conjunctiva, as well as damage the nervous system, liver, and kidneys.
Skin irritations develop within hours after contact and then subside over the next few days.
Supplement
Poisoning by spurge species primarily occurs through three exposure routes: oral ingestion, skin contact, and eye contact. With oral ingestion, animals chew or swallow plant parts, and even small amounts of the milky sap can be enough to cause irritation in the mouth and throat area. However, the bitter taste often leads animals to avoid ingesting larger quantities.
Skin contact usually occurs when animals brush through plant stands or come into contact with broken plant parts. The exuding milky sap can cause irritation on the skin, especially in thinly haired areas. Eye contact is particularly problematic, as it can lead to severe corneal damage if the milky sap gets directly into the eye.
The toxic active ingredients in spurge plants include various terpene compounds that exert different effects in the organism. Diterpenes are highly irritating to mucous membranes and can trigger inflammatory reactions. Triterpene saponins affect cell membrane permeability and can lead to tissue damage. Some species also contain phorbol esters, which act as tumor promoters and can activate protein kinase C.
Toxicity varies depending on the plant species, plant age, and season. Generally, the milky sap is more concentrated in young, growing plant parts. Furthermore, studies have shown that the toxin concentration can be higher during the flowering season.
Mechanism of action
The toxicity is based on a complex mixture of irritating and cytotoxic substances, especially diterpene esters, phorbol esters, and euphorbone, which are present in high concentrations in the milky sap. Contact with injured plant parts is particularly critical, as the white, sticky milky sap easily transfers to skin, mucous membranes, or eyes.
1. Toxicologically Relevant Ingredients
| Main active ingredients | Toxic effect |
| Diterpene esters (e.g., phorbol esters) | Inflammation induction, cytotoxicity |
| Euphorbone | Irritation of mucous membranes and skin |
| Latex (milky sap) | highly irritating on skin or mucous membrane contact |
2. Mechanisms of Action after Ingestion or Contact
A) Irritation of Mucous Membranes and Skin
- Diterpene esters have a strong irritating to corrosive effect on epithelia.
- Mechanism:
- Activation of protein kinase C (PKC) in epithelial cells → inflammatory reaction
- Release of cytokines and prostaglandins
- Cell membrane destruction, apoptosis-inducing
- Clinical consequences:
- Salivation, oral inflammation, difficulty swallowing
- Stomatitis, glossitis, gastroenteritis
- Eye irritation up to conjunctivitis and keratitis with eye contact
B) Gastrointestinal Toxicity
- After oral ingestion, the following occur:
- Vomiting, sometimes bloody
- Diarrhea, abdominal pain
- Irritation of the gastric mucosa up to gastritic erosions
- In rare cases (especially in puppies/kittens) → electrolyte disturbances, circulatory symptoms
C) Systemic Effect (Rare, with Large Intake)
- At very high doses or in particularly sensitive animals:
- CNS depression or seizures
- Liver or kidney toxicity due to secondary metabolic stress
- Hemorrhagic gastroenteritis
- Probably secondary to cytotoxicity and inflammatory mediators
3. Species Differences
Dog:
- Often eats parts of houseplants
- Mainly shows gastrointestinal symptoms and salivation
- Risk: Aspiration of vomit with heavy salivation
Cat:
- Very sensitive to oral or dermal intake
- Often licks contaminated fur after skin contact
- Eye contact or oral ingestion → often severe stomatitis and conjunctivitis
4. Summary of Toxic Effects
| Structure | Toxic mechanism | Consequences for dog/cat |
| Mucous membranes | Irritation by diterpene esters, PKC activation | Stomatitis, hypersalivation, vomiting |
| Skin and eyes | Irritation by latex | Dermatitis, conjunctivitis, blepharospasm |
| GIT | Irritation, inflammation, cytotoxicity | Diarrhea, abdominal pain, gastrointestinal ulcers |
| Systemic | (rare) Inflammation, cell breakdown | Apathy, elevated liver values, cerebral symptoms |
Conclusion
Spurge plants (Euphorbia) contain irritating, cytotoxic diterpene esters that can cause severe symptoms in dogs and cats after contact with mucous membranes, skin, or oral ingestion. Symptoms are usually local (inflammatory), and in rare cases, systemic. Due to the high irritant potential of the milky sap, these plants should be kept inaccessible to pets.
Symptoms of intoxication
First symptoms due to inflammation in the gastrointestinal tract and kidneys are:
- Vomiting
- Bloody diarrhea
- Colic-like pain
- Kidney inflammation
- Bloody urine
Damage to the nervous system includes
- Dilated pupils
- Gangunsicherheiten
- Disorientation
- States of excitation
- Seizures
- Paralysis
Damage to the cardiovascular system
- Circulatory collapse
- Cardiac Arrhythmias
Supplements
Clinical signs of spurge poisoning typically develop within a few hours after exposure and vary depending on the route of exposure and the amount ingested. With oral ingestion, affected animals first show local irritation in the mouth and throat area. Increased salivation (hypersalivation), which can often be foamy, is characteristic. Animals show signs of discomfort such as licking their lips, shaking their heads, or rubbing their mouths on objects.
If larger quantities are ingested or in particularly sensitive animals, gastrointestinal symptoms may occur. These include vomiting, which may sometimes be bloody, and diarrhea. In severe cases, colic-like abdominal pain may occur, manifesting as a tense posture, restlessness, or expressions of pain.
Skin contact leads to dermatitis with redness (erythema), swelling (edema), and in severe cases, blistering. Skin reactions typically develop within hours after contact and can last for several days. Affected animals show increased licking, scratching, or rubbing of the affected areas.
Eye contact with the milky sap is particularly dangerous. This leads to conjunctivitis with redness, swelling, and increased tearing. In severe cases, keratitis with corneal opacity and potentially permanent damage can occur.
In severe poisonings, systemic symptoms may also occur, indicating involvement of the nervous system. These include dilated pupils (mydriasis), coordination disorders (ataxia), disorientation, states of excitement up to seizures and paralysis. The cardiovascular system can also be affected, which can manifest as cardiac arrhythmias or, in extreme cases, circulatory collapse.
In cats, symptoms may be more pronounced than in dogs due to their unique metabolic physiology, especially regarding neurological signs.
Diagnosis
The diagnosis of spurge poisoning is primarily based on the animal’s history, clinical symptoms, and, if applicable, the detection of plant residues. A thorough questioning of the pet owner is essential to obtain information about possible exposure sources. This should include asking about the presence of spurge plants in the household or garden, as well as any observed chewing or playing behavior of the animal with plants.
The clinical examination includes a thorough inspection of the oral cavity for signs of irritation or chemical burns, as well as an assessment of the hydration status in animals with vomiting or diarrhea. If eye contact is suspected, an ophthalmological examination with fluorescein staining is indicated to identify corneal defects.
Laboratory diagnostic measures can be used supportively, but are not specific for spurge poisoning. A blood count can provide indications of inflammatory reactions, while blood chemistry may show changes in liver or kidney values in severe poisonings. In selected cases, a urine examination may be useful to assess possible kidney involvement.
Definitive identification of the responsible plant is helpful for diagnosis. Pet owners should, if possible, bring plant parts or take photos of the suspicious plants. If uncertain, consulting a botanist or using specialized plant databases can help with identification.
Differential diagnosis must exclude other poisonings with similar symptoms, especially those that also cause mucous membrane irritation, such as contact with corrosive agents or other irritating substances. Non-toxic causes of vomiting, diarrhea, or neurological symptoms should also be considered.
Therapeutic principles
There is no antidote.
Decontamination particularly concerns the eyes and skin. If the eyes are affected, prolonged (15 min) rinsing with lukewarm water with open eyelids is particularly important. Otherwise, severe corneal lesions with opacities and tissue dissolution could occur.
Further therapy is symptomatic.
The treatment of spurge poisoning is primarily symptomatic, as no specific antidote exists. Therapeutic measures depend on the route of exposure, the severity of symptoms, and the time since ingestion.
In case of skin contact, thorough decontamination is paramount. The affected skin areas should be washed with lukewarm water and mild soap to remove the adhering milky sap. Care should be taken to ensure that the wash water does not get into the eyes. After cleaning, cooling, soothing compresses or anti-inflammatory ointments can alleviate local irritations.
Eye contact with the milky sap is particularly critical. Immediate and extensive rinsing with physiological saline solution or lukewarm water for at least 15–20 minutes is required. Rinsing should be done with open eyelids to reach all areas of the eye. After the initial rinse, a veterinary examination is essential to assess the extent of possible corneal damage. Depending on the findings, local antibiotics, anti-inflammatory eye drops, and pain-relieving medications may be used.
In case of oral ingestion, gastric lavage may be considered if ingestion occurred less than 1–2 hours ago and there are no contraindications. Administration of activated charcoal (1–4 g/kg body weight) can reduce the absorption of toxins not yet absorbed. In case of vomiting and diarrhea, fluid and electrolyte therapy is essential to prevent dehydration. Antiemetics such as maropitant (1 mg/kg s.c.) can be used to control vomiting.
For gastrointestinal symptoms, gastric mucosal protectants such as sucralfate (0.5-1 g per animal every 8–12 hours) and proton pump inhibitors such as omeprazole (0.5-1 mg/kg once daily) can help alleviate symptoms. For severe pain, analgesics such as butorphanol (0.2-0.4 mg/kg i.m. or i.v.) or buprenorphine (0.01-0.02 mg/kg i.v.) can be used.
Neurological symptoms require close monitoring and, if necessary, the administration of anticonvulsants such as diazepam (0.5-2 mg/kg i.v.) for seizures. In severe cases, hospitalization with intensive care may be necessary.
Prognosis & follow-up care
The prognosis for spurge poisoning is generally favorable, provided that appropriate and timely treatment is given. Most animals recover completely within a few days to weeks, depending on the severity of the poisoning and the organ system affected.
With skin contact, irritations typically subside within 3–5 days without leaving permanent damage. Eye injuries have a variable prognosis; superficial corneal lesions mostly heal without complications, while deeper ulcerations can lead to scarring and permanent visual impairment. Regular follow-up by a veterinarian with ophthalmological experience is essential for eye involvement.
Gastrointestinal symptoms usually respond well to symptomatic therapy and subside within 24–48 hours. In severe poisonings with systemic involvement, especially with neurological or cardiovascular symptoms, recovery time may be longer and require closer monitoring.
Aftercare includes follow-up examinations to assess the healing process, depending on the severity of the poisoning. For animals with gastrointestinal symptoms, a bland diet may be advisable for a few days. Animals with eye involvement often require longer-term local therapy and regular monitoring of the healing process.
To prevent further poisoning cases, pet owners should be informed about the risks of spurge plants. It is advisable to remove known toxic plants from the pet’s environment or make them inaccessible. Alternatively, non-toxic ornamental plants can serve as substitutes. For garden plants, attention should be paid to native spurge species, which are particularly present in spring and summer.
Research outlook
Research into spurge poisoning in pets is continuously evolving. Current studies focus on several key areas that could improve the understanding and management of these poisonings.
An important research area concerns the more precise characterization of toxic compounds in different spurge species and their specific mechanisms of action. Modern analytical methods such as high-performance liquid chromatography (HPLC) and mass spectrometry enable more precise identification and quantification of toxins. These findings could lead to the development of more specific treatment approaches.
Increasingly, the focus is also on the different sensitivities of various animal species and breeds to spurge toxins. Initial studies suggest that cats may react more sensitively than dogs due to their particular metabolic physiology. Within the dog population, there also appear to be breed-specific differences in toxin sensitivity.
In the field of diagnostics, new rapid tests are being researched that could enable faster identification of specific plant toxins. Such tests would be particularly valuable in emergency situations when the responsible plant cannot be identified.
Therapeutically, attention is focused on improved treatment protocols for corneal lesions after eye contact with spurge sap. Innovative approaches such as the application of amniotic membranes or special corneal adhesives show promising results in the treatment of severe corneal defects.
Epidemiological studies investigate the seasonal and regional distribution of poisoning cases to better understand risk factors and develop targeted prevention strategies. Databases from poison control centers provide valuable information on the frequency and severity of spurge poisonings compared to other plant poisonings.
These research efforts contribute to continuously improving the management of spurge poisoning in pets and could lead to more specific treatment options in the future.
Frequently asked questions (FAQs)
- How do I identify spurge plants in my garden or home?
Spurge plants can be identified by the characteristic milky sap that exudes when the plant is injured. Common houseplants include poinsettia, crown of thorns, and croton. In the garden, various spurge species with typical inflorescences and opposite leaves can be found. - Are all spurge species equally toxic to my pet?
No, toxicity varies considerably between species. While some, like the poinsettia, are comparatively mildly toxic, other species, such as the Caper Spurge, contain significantly higher concentrations of toxins. - Which parts of spurge plants are particularly toxic?
The milky sap contains the highest concentration of toxic substances. It is found in all plant parts but particularly exudes when stems and leaves are injured. - My cat nibbled on a poinsettia – is that an emergency?
Not necessarily. Observe your pet for symptoms such as salivation, vomiting, or mouth irritation. For mild symptoms, rinse the mouth with water. For more severe symptoms or eye contact, you should consult a veterinarian immediately. - Can my dog die from spurge poisoning?
Fatalities are rare, as most animals only ingest small amounts. However, severe poisonings with systemic involvement can be life-threatening, especially if timely treatment is not provided. - How do I treat eye contact with spurge sap in my pet?
Immediately rinse the eye for at least 15-20 minutes with lukewarm water or physiological saline solution. Keep the eyelids open and then consult a veterinarian immediately. - Are there non-toxic alternatives to popular spurge plants for my home?
Yes, there are many pet-friendly alternatives. Instead of poinsettia, you can choose Christmas cactus or azaleas; instead of croton, Calathea species or ferns are suitable. - How long does it take for my pet to recover from spurge poisoning?
For mild poisonings with mainly local symptoms, recovery is expected within 24–48 hours. In more severe cases, especially with eye involvement, recovery can take several weeks. - Are certain dog or cat breeds more susceptible to spurge poisoning?
Current research suggests possible breed-specific differences in sensitivity, but there is no clear evidence yet for specific breed predispositions. Generally, cats seem to react more sensitively than dogs. - Can I take preventive measures to protect my pet from spurge poisoning?
The most effective prevention is to remove toxic plants from your pet’s environment or place them in inaccessible locations. Inform yourself about toxic plants in your garden and offer your pet safe chewing alternatives such as special cat grass.
Literature
- Cortinovis C, Caloni F. Epidemiology of intoxication of domestic animals by plants in Europe. The Veterinary Journal. 2013;197(2):163-168.
- Poppenga RH, Gwaltney-Brant SM. Small Animal Toxicology Essentials. 2nd ed. Wiley-Blackwell; 2021.
- Milewski LM, Khan SA. An overview of potentially life-threatening poisonous plants in dogs and cats. Journal of Veterinary Emergency and Critical Care. 2020;30(2):139-150.
- Bertero A, Fossati P, Caloni F. Indoor poisonous plants for cats: European advice for cat owners. Journal of Feline Medicine and Surgery. 2020;22(5):442-448.
- Fitzgerald KT. Lily toxicity in the cat. Topics in Companion Animal Medicine. 2010;25(4):213-217.
- Löwe G, Löwe O. Poisoning in Dogs and Cats – A Veterinary Guide. 2nd edition. Kreuztal: Kynos-Verlag. 2021; 208 p.