Grazing cattle and horses are the most common victims of spotted water hemlock poisoning. The roots are the most poisonous part of the plant, followed by young leaves. They have the same neurological effects on both animals and humans. The toxins bind to specific receptors on the nerve cells and prevent them from functioning normally. This induces the nerve cells to go into a state of constant overactivity, which causes the animal to experience aggressive seizures and other neurological complications. Symptoms of poisoning in animals also include excessive salivation, nausea, vomiting, vigorous chewing, teeth grinding, muscle degeneration, and respiratory paralysis. Spotted water hemlock poisoning can often be fatal. First symptoms usually appear very rapidly, and death may ensue within 15 minutes to 3 hours after the first signs are displayed. Spotted water hemlock can present a great danger to dogs, who like to explore, dig and chew on plants out of curiosity. This plant grows near streams and ponds, so pay close attention to your pets if you walk them in wetlands or near bodies of water within the plant's native range.