Milfoil is native to Asia, Europe, and North America. It is a hardy plant that flourishes with very little maintenance. If ingested by your dog, it can cause symptoms of gastrointestinal upset as well as other toxicity symptoms. Since the symptoms of toxicity are very vague, if you are able to bring in a piece of the plant your dog ingested, it will help speed up the diagnostic process. In most cases of toxicity from ingestion, the dog will just need supportive therapies from the veterinarian. He will likely recover without any long term side effects and will be back to his normal self very soon.

Milfoil, also commonly known as yarrow, can be toxic to your dog. If you suspect he ingested any amount of it, contact your veterinarian.

If your dog ingests milfoil plant, he may develop symptoms of poisoning. Symptoms of milfoil toxicity may include: 

The milfoil plant belongs to the Asteraceae family with the scientific name of Achillea millefolium. In addition to milfoil, this plant is also commonly known as yarrow. The milfoil plant grows to about 3 feet in height with leaves with a fern-like appearance. The flowers bloom in clusters of 20 to 25 yellowish-white delicate disk flowers. Sometimes these flowers bloom in a pink color, but rarely.

Milfoil contains the toxic properties including glycoalkaloids (achillein), sesquiterpene lactones, and monoterpenes. Achillein is a brownish-red substance that is very bitter and acts as a diuretic. Sesquiterpene lactones do have some therapeutic potential and are commonly used in herbal remedies. However, the properties that make it useful also make it toxic. Monoterpenes also have their beneficial properties, but in excess causes toxicity symptoms.

Symptoms of milfoil poisoning are very vague; many things can cause the symptoms listed, and therefore, coming to a proper diagnosis can be difficult. There are a number of diagnostic tests the veterinarian may need to perform. When you first arrive at the clinic, she will begin by collecting a history from you. She will want to know what your dog possibly could have come into contact with within the past 24 hours. She will perform a physical exam on your dog to check his vitals and note any other symptoms he may be experiencing.

If your dog vomits while he is at the clinic, the veterinarian will examine the regurgitated contents for clues as to what he ingested. If he is having diarrhea, a sample will be collected and diagnostics will be run to rule out other possible causes such as internal parasites or bacterial overgrowth. The symptom of depression can be caused by many things so there is no test by which the cause of this can be determined.

The symptoms of hypersalivation and anorexia are secondary to the nausea/vomiting. These are very common symptoms when your dog ingests something he shouldn’t. However, these symptoms can also be caused by other types of illnesses so they are not a definite indicator of toxicity.

If your dog has not vomited since ingesting the milfoil plant, the veterinarian may induce vomiting to rid his stomach of any remaining plant contents. If this is unsuccessful, she may administer activated charcoal to bind to the toxin in your dog’s system before the blood stream can absorb any more of it. It will also act as a protective layer for your dog’s gastrointestinal tract. If she feels it is needed, she may decide to flush your dog’s stomach; however, this can involve putting your dog under anesthesia and is typically only applied in the more serious toxicity cases.  

Fluid therapy with electrolytes will be started almost immediately once blood work is completed. Not only will this correct any degree of dehydration your dog is experiencing, but it will also flush the toxin from his system quicker. Even if your dog is not drinking, the fluids will make your dog need to urinate and therefore pass the toxin out of his system. The more fluids he receives, the more he will need to urinate; the faster he needs to urinate, the faster the toxin will leave his system. The goal is to get your dog to urinate quickly and frequently to pass the toxin before it is absorbed.

Poisoning from milfoil in dogs may range from mild to severe. If you suspect your dog has ingested something he should not have and is now having a reaction, the sooner you get him to the veterinarian the better. Decontamination is key to recovery in any toxicity case. Most dogs recover well with the help of supportive therapies.