THE Most Toxic Plant to Your Dog


It may look soft, delicate and even docile, but this wildflower is one of the most toxic – and fast acting – plants your dog can ingest (even in a small amount).

(It’s also highly poisonous to humans.)

It’s called Water Hemlock and is a member of the carrot family. It typically grows in wet areas like marshes and swamps, damp pastures and along riverbanks, ponds, streams, irrigation ditches, reservoirs and other water edges in both North America and parts of Europe.

Water hemlock is also known as:

  • beaver poison
  • poison parsley
  • muskrat weed
  • poison parsnip
  • spotted water hemlock
  • western water hemlock
  • cowbane/spotted cowbane
  • bulblet-bearing water hemlock

If ingested, the violent effects of toxic poisoning may become evident within a few minutes (from a toxin called cicutoxin, an aggressive, poisonous stimulant that attacks the nervous system) and include:

  • Drooling
  • Nervousness/agitation/weakness
  • Dilated pupils
  • Seizures and/or twitching
  • Rapid heart rate/difficulty breathing/asphyxiation/choking
  • Coma
  • Death from respiratory paralysis death (occurring between 15 minutes and 2 hours after the first initial signs of poisoning).

While the highest levels of its toxin is found in the roots, all parts of the water hemlock are poisonous and dog lovers should never let their dog get anywhere near it.

A side note, the water hemlock has a strong carrot-like odor which could attract curious dogs.

If you suspect your dog has come into contact with water hemlock, seek immediate emergency veterinary care.

To learn more about water hemlock and its potential dangers:


  • Hi there is it possible that dogs can be allergic to the smell as my dog has been unable to walk near this plant with out reverse sneezing and has like what sounds like s blocked nose sniffing all the time , there is a huge amount in are park and the council says it’s not a problem unless they eat it , any advice please thanks for your time ,

    • Thanks for your question and let me say first, I am not a veterinarian.

      However, given how toxic this plant is to both dogs and humans, I would avoid it completely to keep you and your dog safe. (A source warns that humans even breathing in the pollen can make you ill! )

      In an article co-authored by Dr. Pippa Elliott, a veterinarian with other 30 years of experience, she says, “Do not touch hemlock bare-handed. Hemlock is dangerous to people and other animals, as well as dogs. Even a small amount can literally kill a horse. In fact, your dog does not need to ingest the plant for it to put them at risk.

      Also, given that this toxic plant can cause severe (and life-threatening) issues including seizures, difficulty breathing, cardiovascular issues and nervous system damage (in as little as 15 minutes), I would avoid any areas (direct and surrounding) where this plant is present. It’s just not worth the risk.

      Here’s some vet information on reverse sneezing as well:
      “Reverse sneezing and “regular” sneezing are closely related reflexes. The purpose of both is to expel an irritant from the upper part of the respiratory tract (coughing plays the same role further down). Irritation to the nasal passages (e.g., a snout-full of dust) causes “regular” sneezing. Irritation to the nasopharynx (the area that lies behind the nasal cavities and above the soft palate) causes dogs to “reverse” sneeze.”

      Also, “when a pet experiences frequent bouts of reverse sneezing, it’s time to take notice. Excessive reverse sneezing indicates that whatever is irritating your pet’s nasopharynx isn’t being expelled.”

      And finally, “possible causes of excessive reverse sneezing include allergies, infections, masses, foreign material (e.g., grass awns), or anatomical abnormalities that affect the nasopharynx.” (

      I hope this information helps, stay safe please!

  • Wow! Had no idea. I’ll be on the lookout given that the first link was reported in my home state. We see a lot of lacy plants similarly looking on our daily walk-abouts and will avoid them totally.

  • Thanks for this information I will keep my eyes open, are there other plants that look just like it, which are not dangerous?

    • Interesting question … here’s some additional info, hope this helps!

      Water hemlock bears a close resemblance to other members in the family Apiaceae and may be confused with a number of other edible and poisonous plants.

      The Apiaceae family (or Umbelliferae), commonly known as the celery, carrot or parsley family, are a family of mostly aromatic plants with hollow stems. The family, which is named after the type genus Apium, is large, with more than 3,700 species spread across 434 genera; it is the 16th-largest family of flowering plants.[1] Included in this family are the well-known plants: angelica, anise, arracacha, asafoetida, caraway, carrot, celery, Centella asiatica, chervil, cicely, coriander (cilantro), culantro, cumin, dill, fennel, hemlock, lovage, cow parsley, parsley, parsnip, cow parsnip, sea holly, giant hogweed and silphium (a plant whose identity is unclear and which may be extinct).

      The common name hemlock may also be confused with poison hemlock (Conium maculatum).

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