Larkspurs (Delphinium species) have the potential to be highly toxic to dogs, although pets generally don’t eat them. These flowering plants contain diterpene alkaloids, which can cause health concerns ranging from vomiting to death. Larkspurs also contain protoanemonin, a bitter and irritating toxin the plants produce to dissuade animals from eating them.
Larkspurs tend to become less toxic as they mature, according to the ASPCA. The alkaloids in these plants cause neuromuscular blocking because they inhibit a neurotransmitter called acetylcholine. You may see drooling, vomiting or constipation after your dog has eaten larkspurs. These signs may be caused by the alkaloids or by the protoanemonin, which generally prevents dogs from eating a large amount of the plants. Due to the alkaloids, your dog’s heart may not beat normally, slowing down or stopping. Your dog may develop respiratory paralysis. The alkaloids may also affect your pooch’s nervous system, causing tremors, convulsions or limb paralysis.
Rapid treatment is necessary if your dog is showing signs of intoxication. Your veterinarian may induce vomiting or give your dog medication to prevent absorption of the toxins. Atropine may be given to counteract the irregular, slow heart rate. Your vet will treat other symptoms present, including the vomiting and potential constipation.