Dog Dies Within An Hour After Chewing Deadly Plant At Popular Outdoor Reservoir

There are many toxic wild plants that can poison pets, but one of the most lethal took a dog’s life within one hour. A 3-year-old Border Collie was playing at Horsetooth Reservoir in Colorado with her family when she chewed on water hemlock.

Shortly after, she lost all motor function and passed out and died en route to hospital, KDVR News reported. Although water hemlock is not a plant that normally appeals to dogs, it is important to be aware that just  a few leaves of the plant can kill a large dog within 2 hours.

Some dogs have even been poisoned from drinking water that had been contaminated with trampled water hemlock roots!

“Water hemlock is one of the most lethal plants in North America,” Dr. Dawn Duval, Department of Clinical Sciences associate professor at Colorado State University told KDVR News. “It’s a plant that grows in very moist areas, around ditches and lakes.” 

She added, “This dog just got unlucky and kind of started playfully chewing on a plant that it shouldn’t be chewing. Water hemlock is not a plant that would be particularly appealing to dogs.”


Water Hemlock (Cicuta maculata). Photo credit: wikipedia

Water hemlock is found throughout North America and grows near rivers, streams and lakes and other marshy areas. All parts of the plant are poisonous, with the roots being the most toxic.

water hemlock

Water hemlock grows in marshy areas and on the edges of rivers, lakes and streams.

Farmers regularly monitor their pastures for the plant to keep it away from livestock. It’s a tall, branching plant and usually grow to 3 to 6 feet (1 to 2 meters).

It blooms in June and July with white flowers and it has narrow, serrated leaves with twice dividing leaflets. Cow parsnip and water parsnip often get confused with water hemlock. The roots are toxic at all times, even when dry.


Water hemlock leaves are serrated and narrow.

If water hemlock is consumed, symptoms begin within a matter of minutes and include drooling, muscle twitching and seizures. The dog will appear to have dilated pupils and nervousness and shortly after experience convulsions and respiratory paralysis and then death.

If a non-lethal dose is consumed and the animal survives for 4 to 6 hours, there is a chance at recovery but there may be temporary or permanent damage to their heart or skeletal muscle.

If you see your dog eating water hemlock, especially the roots, get him away from the plant and call a veterinarian immediately. Try emergency measures to induce vomiting, but it should be noted that the toxin acts very quickly.

The key prevention is to identify and avoid the plant altogether and to keep your dog from digging and chewing wild plants while outdoors.

Please share this information with the pet parents you know.

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