Yes, all parts of the delphinium plant (genus Delphinium) are considered poisonous to both humans and pets. The primary toxic agents are a group of diterpenoid alkaloids, including methyllycaconitine (MLA), delphinine, ajacine, and others. These compounds are potent neurotoxins that the plant produces as a natural defense mechanism against herbivores. They are concentrated in the new growth, young leaves, and seeds, making these parts particularly dangerous. The plant's strategy is to deter animals from consuming it, thereby ensuring its survival and ability to reproduce.
The diterpenoid alkaloids function as neuromuscular blockers. They interfere with the normal function of neurotransmitter receptors, specifically nicotinic acetylcholine receptors. This disruption prevents nerve cells from communicating properly with muscle cells, leading to a range of severe neurological and muscular symptoms. In humans and animals, ingestion can cause intense burning sensations in the mouth and throat, excessive salivation, vomiting, and diarrhea. As the toxins affect the nervous system, symptoms can progress to muscle weakness, tremors, stiffness, and incoordination. In severe cases, paralysis can set in, potentially leading to respiratory failure and death if untreated.
Pets, particularly dogs, cats, and horses, are at significant risk from delphinium poisoning. Curious pets may chew on the attractive flowers or foliage. Horses are especially vulnerable as they may encounter these plants in pastures or as ornamentals near fences. The dosage required for a toxic reaction is relatively low compared to body weight; even a small amount of plant material can cause serious illness in a medium-sized dog or a fatal reaction in a horse. The rapid onset of symptoms means that veterinary attention is urgently required. There is no antidote, so treatment is primarily supportive, including decontamination (inducing vomiting if advised), administering activated charcoal, and providing intravenous fluids and medications to control symptoms.
For humans, the risk of severe poisoning is generally lower in adults due to the larger body mass required for a lethal dose and the unpleasant taste that discourages consumption of a large quantity. However, children are at a much higher risk due to their smaller size and natural curiosity. Accidental ingestion of seeds or flowers can lead to serious medical emergencies. Gardeners should also exercise caution when handling the plants, as the sap can cause skin irritation and dermatitis in sensitive individuals. It is advisable to wear gloves when pruning or cutting delphiniums to avoid any contact with the plant's juices.
