Iceland moss Toxic?

Updated 2026-03-06| 3 min read| 4,465 found this helpful

Cetraria islandica (L.) Ach. (syn. Lichen islandicus L.)

No confirmed poisoning cases associated with Iceland moss are recorded in published peer-reviewed literature for humans or any animal species.

Despite no reported adverse events, Iceland moss is not considered suitable for use as feed for pets, livestock, or working animals.

The species carries confusion risk with other potentially toxic lichen species that may cause harm if ingested.

FAQ

Is Iceland moss toxic to Humans?

No documented poisoning symptoms available; consult a medical professional immediately if accidental ingestion of large quantities or lookalike species occurs. (Non-toxic)

Is Iceland moss toxic to Cats?

No documented feline poisoning symptoms available; contact a veterinarian immediately if unusual symptoms appear post-ingestion. (Non-toxic)

Is Iceland moss toxic to Dogs?

No documented canine poisoning symptoms available; contact a veterinarian immediately if unusual symptoms appear post-ingestion. (Non-toxic)

Is Iceland moss toxic to Horses?

No documented equine poisoning symptoms available; contact a veterinarian immediately if unusual symptoms appear post-ingestion. (Non-toxic)

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Toxicity Details

Humans

Non-toxic

No documented poisoning symptoms available; consult a medical professional immediately if accidental ingestion of large quantities or lookalike species occurs.

Cats

Non-toxic

No documented feline poisoning symptoms available; contact a veterinarian immediately if unusual symptoms appear post-ingestion.

Dogs

Non-toxic

No documented canine poisoning symptoms available; contact a veterinarian immediately if unusual symptoms appear post-ingestion.

Horses

Non-toxic

No documented equine poisoning symptoms available; contact a veterinarian immediately if unusual symptoms appear post-ingestion.

Toxicity Snapshot

Toxic PartsNo specific toxic parts identified; no poisoning cases reported in available literature, but the entire plant is unsuitable for use as animal feed.

Exposure RoutePrimary potential exposure route is accidental or intentional ingestion; no dermal or inhalation toxicity has been reported.

Toxic CompoundsNo toxic compounds have been formally linked to adverse effects from this species in the provided scientific literature

First Aid & Prevention

First 30 Minutes

• Remove any remaining lichen material from the mouth of the exposed human or animal immediately.
• Rinse the mouth thoroughly with clean, cool water to eliminate residual plant debris.
• Do not induce vomiting unless explicitly directed to do so by a licensed medical or veterinary professional.

Contact Vet Immediately

• If your animal has ingested large quantities of unconfirmed lichen material that may be a toxic lookalike.
• If unusual symptoms (gastrointestinal distress, lethargy, loss of appetite) appear after lichen ingestion.
• If you are uncertain of the identity of the lichen ingested by your pet or livestock.

Prevention

• Never use Iceland moss as a feed ingredient for any pet, livestock, or working animal species.
• Learn to distinguish Iceland moss from toxic lookalike lichens before foraging in regions where both grow.
• Store any Iceland moss intended for human use securely out of reach of children and animals.

Treatment & Prognosis

• Seek professional medical or veterinary guidance immediately if adverse symptoms appear post-ingestion.
• Administer supportive symptomatic care as prescribed by a qualified care provider.
• Monitor the exposed individual for 24 hours post-ingestion to catch any potential delayed adverse reactions.

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Professional Toxicology

Scientific NameCetraria islandica (L.) Ach. (syn. Lichen islandicus L.)

AliasesBlood lung moss、Fever moss、Staghorn lichen、Barley lichen、Iceland lichen

Toxicity Grade

HumansNon-toxic

CatsNon-toxic

DogsNon-toxic

HorsesNon-toxic

Target Organs

No target organs for toxicity have been identified in available research

Mechanism of Action

• No specific toxic mechanism has been identified for this species, as no confirmed poisoning events have been documented

Other Species Risk (CliniTox)

Information from CliniTox veterinary text.

Ruminant livestock (cattle, sheep, goats): No confirmed poisoning cases reported, but use as a feed component is explicitly not recommended per toxicology guidance

Small companion mammals (rabbits, guinea pigs, hamsters): No documented adverse events, but ingestion of large quantities is not advised

Confusion Risk

The following plants look similar and may be confused:

Wolf lichen Letharia vulpina

Both are fruticose lichens native to cold northern habitats; wolf lichen is bright sulfur-yellow (vs. grey-green to brown Iceland moss) and highly toxic to all animal species.

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Related Toxic Plants

Wolf lichen

Letharia vulpina

Severe toxicity, fatal to canines and livestock in small doses

Old Man's Beard

Usnea barbata

Low to moderate toxicity, causes gastrointestinal upset and liver irritation with high or chronic intake

Perforated Ruffle Lichen

Parmotrema perforatum

Low toxicity, may trigger mild allergic reactions or gastrointestinal discomfort in sensitive individuals

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Data Sources

1. CliniTox (Universität Zürich)

This information is for reference only and does not constitute medical advice. If ingestion or poisoning is suspected, seek medical or veterinary attention immediately.

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