Fleabane Poisoning in Dogs

The Erigeron family of plants is a subsection of the daisy family Asteraceae. Most commonly referred to as Fleabane due to their ability to repel fleas, the may also be known as showy daisy, seaside daisy, horseweed, and beach aster. These plants are often considered to be a reasonably safe pest deterrent to plant in gardens with dogs, and can be found growing wild in many areas. The sap, however, is known to cause a contact rash and ingesting this plant may cause gastrointestinal upset in canines, including vomiting and diarrhea. 

This plant should not be confused with Mentha Pulegium, or pennyroyal, another plant that occasionally goes by the name of fleabane. Mentha Pulegium is highly toxic and can cause acute liver and lung damage.

Fleabane refers to several wildflowers in the Erigeron family of plants. Although they are known as effective flea repellents, these flowers may cause gastrointestinal distress when ingested.

Plants in the Erigeron family are mildly toxic, sometimes inducing vomiting and diarrhea. If sufficient quantities of the vegetation are consumed, it can result in dangerous intestinal obstructions. Symptoms of intestinal blockage generally occur around 24 hours after the consumption of something indigestible. 

Symptoms of severe intestinal blockage could include:

• Abdominal pain
• Distended abdomen
• Fever
• Inability to eliminate
• Loss of appetite
• Shock
• Straining on defecation
• Vomiting

Types 

Several plants are effective in repelling fleas and other insects, with varying safety levels for your pet:

Natural remedies that known to be acutely toxic to canines - These plants and their essential oils should not be used on your pet unless it is under direct veterinary supervision:

• Eucalyptus
• Garlic
• Patchouli
• Pennyroyal
• Pyrethrum plant

Remedies that might be effective but may also produce uncomfortable side effects - Use these medications cautiously and contact your veterinarian right away if you see any side effects developing:

• Citronella
• Clove
• Mugwort
• Neem
• Rosemary

Natural remedies that are generally safe to use with dogs - These herbs are not known to have any negative interactions for canines:

• Basil
• Catnip
• Lavender
• Peppermint
• Rose geranium
• Sage
• Thyme
• Turmeric

The toxin in the plants of the Erigeron family is not well recorded, but many of the varieties are known to contain essential oils which may be the cause of gastrointestinal upset. The symptoms are not known to be severe, however, even plants with minimal toxicity can be a source of hazards. Although the risk factor for these situations is small, close observation of your pet’s behavior is the safest way to ensure prompt medical treatment for unexpected happenings. 

Bee stings - Bright flowers like fleabane are highly attractive to stinging insects like bees and wasps. Insect stings are generally a minor inconvenience and can be handled at home. However, massive swelling may occur if your pet develops an allergy to the venom in bee stings and the animal should be rushed to the veterinarian before anaphylactic shock can set in. 

Intestinal blockages - The canine gastrointestinal system is not designed to handle large quantities of vegetation. Although most dogs do not tend to do more than sample wildflowers or garden plants, some canines may develop an overwhelming craving for nonfood items. This disorder is known as pica and can cause your dog to consume copious quantities of inappropriate substances, such as wood or plant material, which can lead to intestinal blockages.     

Pesticides - Even non-toxic plants may be treated with decidedly toxic pesticides. If symptoms of poisoning occur after your dog tastes a plant that is not in your own garden you should contact your veterinarian immediately. Canines poisoned by pesticides will exhibit signs such as vomiting, tremors, seizures, and breathing difficulties.

As fleabane plants in the Erigeron family of plants are only mildly noxious, symptoms more severe than mild vomiting or diarrhea are usually due to either misidentification of the plant or a secondary disorder. The health background, dietary habits, access to plants or other potential toxins, oral medications, and current symptoms are all likely to be covered. A thorough physical exam will be performed with particular attention to the stomach and abdomen area, and a complete blood count (CBC), urinalysis, and biochemistry profile will generally be requested to detect if there are any toxins or imbalances in the patient’s system.

If an intestinal blockage is the cause of the distress, the examiner may find a mass where the vegetation has lodged in the digestive tract, or discover that the abdomen is extremely sensitive to touch. This may prompt a recommendation for further imaging and ultrasound, x-ray or even a barium study may be selected to more clearly visualize the possible obstruction.

Treatments are guided by the symptoms and by the ultimate diagnosis. If your dog is showing signs of severe dehydration or is vomiting excessively, he may be admitted to the animal hospital for supportive treatment such as IV supplementation for dehydration and pain mitigation. In cases that are less critical, the initial therapy for dogs exhibiting signs of gastric distress is to withhold food for 12-48 hours (until vomiting has stopped for 12 hours). This method is generally useful because it gives the dog’s digestive system time to recover from the constant contractions. Water and crushed ice can often be offered during this period, but only in small amounts to avoid renewed vomiting or cramping of the stomach.   

In cases of an intestinal blockage, treatments such as fluid therapy are usually utilized to speed the mass through the digestive system. Imaging will be repeated periodically in order to track the movement of the mass until it exits the gastrointestinal system. In severe cases, surgery will be required to remove the mass and correct any damage it caused. In the event of an allergic reaction, such as a response to an insect sting, antihistamines, and anti-inflammatory medications may be prescribed. If the signs are pointing to ingestion of something that was actually toxic, such as an alternate plant or pesticides applied to the plant eaten, then appropriate steps will be taken to remove the particular toxin. These actions could include inducing vomiting, the use of activated charcoal, gastric lavage, and toxin specific antidotes.

If you are required to withhold food from your pet to control the vomiting, only soft, bland foods should be offered once they are cleared for solid food again. This type of diet is easier to digest and may prevent renewed vomiting. The ideal diet at that point will include a mild protein source and one easily digestible carbohydrate. Suitable proteins would be something like unseasoned boiled ground beef, non-fat cottage cheese, or skinless white chicken meat and the starch could include cooked rice, pasta or potatoes. If the vomiting reoccurs, medications to combat the symptoms may be given, such as anti-emetics, gastric protectants or corticosteroids.