How does Larkspur work against parasites and lice?

Larkspur contains diterpenoid alkaloids, such as ajacine and delsoline, which act as neurotoxins. These compounds disrupt nerve signal transmission in parasites, leading to paralysis and death. This mechanism supports its traditional topical use against lice, though specific clinical trials in humans are lacking. The alkaloids affect sodium channels in nerve cells, preventing normal neuromuscular function in the target insects (Evidence Level: C).

Is Larkspur safe to take during pregnancy?

No, Larkspur is considered unsafe during pregnancy and breastfeeding. The plant contains toxic alkaloids that can potentially cross the placenta and affect the developing fetus. Ingestion may also stimulate uterine contractions or cause systemic toxicity. Due to the high risk of poisoning and lack of safety data, pregnant women should strictly avoid both internal and external use of this herb (Evidence Level: C).

What is the safe dosage for Larkspur?

There is no safe internal dosage for Larkspur (Consolida ajacis) due to the risk of severe toxicity. Traditional use is strictly limited to external, topical preparations, such as washes or poultices made from aerial parts, to treat lice. Even topical application requires caution to avoid absorption through broken skin. Internal consumption is contraindicated for all populations (Evidence Level: Traditional).

Does Larkspur interact with any medications?

Specific drug interaction studies for Larkspur are lacking, but significant theoretical risks exist. Because the plant contains cardiotoxic and neurotoxic alkaloids, it should never be combined with heart medications, such as antiarrhythmics, or neuroactive drugs. Internal use is contraindicated, and even topical use could theoretically potentiate the effects of other neurotoxic agents (Evidence Level: C).

Is Larkspur poisonous to humans?

Yes, Larkspur is poisonous to humans if ingested. All parts of the plant, particularly the seeds, contain toxic alkaloids that cause symptoms ranging from nausea and vomiting to muscle weakness and cardiac arrhythmias. While traditionally used topically for parasites, ingestion can lead to severe alkaloid poisoning and requires immediate medical attention (Evidence Level: C).

Larkspur (Consolida ajacis)

PubMed-compiled information sheet

This sheet was compiled from PubMed (NIH) abstracts using AI assistance. Every factual claim is cited to a real PubMed article (see the source list). It has not yet been human-reviewed — confirm with a healthcare provider before use.

Compiled from 30 PubMed articles · model: gemma4:31b

Summary

Larkspur (Consolida ajacis/Delphinium spp.) is a plant containing toxic diterpenoid alkaloids that can cause neuromuscular paralysis and death in livestock [PMID:10091130, PMID:3049494].

Background

Larkspurs are native forbs and arable weeds [PMID:35419604, PMID:36616213]. Nomenclatural revisions have transferred species from the genus Consolida and Aconitella into Delphinium s.lat., specifically within the subgenus Consolida [PMID:34393579].

Traditional uses

In Hungarian ethnobotanical literature (1578-2021), Delphinium consolida was primarily employed to stop bleeding [PMID:36616213].

Active compounds

Larkspurs contain diterpenoid alkaloids, including lycoctonine and 7,8-methylenedioxylycoctonine (MDL-type) [PMID:10091130]. The most toxic are N-(methylsuccinimido) anthranoyllycoctonine (MSAL-type) alkaloids, such as methyllycaconitine (MLA), 14-deacetylnudicauline (DAN), and nudicauline [PMID:10091130]. Consolida ajacis seeds also contain ethyl linoleate and C20 fatty acids such as gondoic acid [PMID:37666618, PMID:34287699].

Mechanism of action

Toxicity results from the blocking of nicotinic acetylcholine receptors in the brain and muscle, leading to neuromuscular paralysis [PMID:10091130].

Clinical evidence

Evidence DLarkspur poisoning in cattle

Clinical signs include labored breathing, rapid and irregular heartbeat, muscular weakness, and collapse [PMID:10091130]. Susceptibility varies by sex (Angus heifers are more susceptible than steers or bulls), age (younger cattle are more susceptible), and breed (beef breeds are more susceptible than dairy breeds) [PMID:31029637, PMID:30055258, PMID:30772914].

Evidence DLarkspur poisoning in mice

Intravenous administration of methyllycaconitine (MLA) caused reluctance to move, trembling, dyspnea, muscular twitches, and convulsions [PMID:12772851]. Susceptibility varies by strain, with the A/J strain being the most susceptible and the 129 strain the least [PMID:19098233].

Safety & adverse effects

Larkspurs are poisonous to cattle and can cause acute intoxication and death from respiratory paralysis [PMID:35419604, PMID:3049494].

Evidence summary

The available evidence is primarily based on veterinary toxicology studies and botanical reviews; there are no human clinical trials for the medicinal use of this herb.

PubMed sources

1.PMID: 35419604 (2022) — Mineral-salt supplementation to ameliorate larkspur poisoning in cattle. · Journal of animal science
2.PMID: 36616213 (2022) — Iconic Arable Weeds: The Significance of Corn Poppy (Papaver rhoeas), Cornflower (Centaurea cyanus), and Field Larkspur (Delphinium consolida) in Hungarian Ethnobotanical and Cultural Heritage. · Plants (Basel, Switzerland)
3.PMID: 10091130 (1999) — Larkspur (Delphinium spp.) poisoning in livestock. · Journal of natural toxins
4.PMID: 34393579 (2021) — Nomenclatural revision of Delphiniumsubg.Consolida (DC.) Huth (Ranunculaceae). · PhytoKeys
5.PMID: 34287699 (2021) — Ectopic expression of cDNAs from larkspur (Consolida ajacis) for increased synthesis of gondoic acid (cis-11 eicosenoic acid) and its positional redistribution in seed triacylglycerol of Camelina sativa.

Larkspur

Sources & Citations