Cuckoo-pint, Arum maculatum, also known as Wild Arum, Arum, Lords and Ladies, Lord-and-Ladies, Devils and Angels, Cows and Bulls, Adam and Eve, Naked Boys, Starch-Root, Wake Robin, Bobbins, and Cuckoo Plant, is a woodland and hedgerow plant in the family Araceae. It is native to much of Europe and western Asia and is often found in shaded woods, hedges, damp ground, old gardens, and naturalized areas. Although it is not a common American houseplant in the same way as Philodendron or Dieffenbachia, it belongs to the same broad calcium-oxalate family and produces the same painful irritant syndrome when chewed or swallowed.

The plant is visually distinctive. In spring, it produces arrow-shaped or spotted leaves and a hooded spathe surrounding a central spadix, giving it the strange and suggestive appearance that explains many of its older folk names. Later in the season, after the leaves may have died back, it can produce a conspicuous spike of bright orange-red berries. Those berries are one of the practical exposure concerns because they may attract children, dogs, or curious animals at a time when the rest of the plant is less obvious.

Cuckoo-pint is sometimes loosely called an Arum Lily, but it should not be confused with true lilies in the genus Lilium. The toxic concern here is not the classic cat kidney-failure syndrome associated with true lilies. This is an Araceae calcium-oxalate plant, and the principal danger is intense local irritation of the mouth, throat, tongue, lips, gastrointestinal tract, and, in serious cases, the upper airway.

One of the more common plant toxins, insoluble calcium oxalate crystals can be found in many popular houseplants, ornamentals, and wild Araceae plants. The vast majority of these plants belong to the Araceae family and cause a similar clinical syndrome. Within the Araceae, genera such as Aglaonema, Alocasia, Arisaema, Arum, Caladium, Colocasia, Dieffenbachia, Monstera, Philodendron, Spathiphyllum, Syngonium, and Zantedeschia contain calcium oxalate crystals in the form of raphides. The Araceae family is one of the most diverse in the plant kingdom, comprising thousands of different species.

When consumed, these plants cause an intense burning sensation of the mouth, throat, lips, and tongue; excessive drooling; choking; gagging; and potentially serious swelling of the throat that could cause difficulty swallowing or the inability to swallow, also known as dysphagia. Symptoms can occur immediately or up to two hours after ingestion and may continue intermittently for a prolonged period after ingestion, depending on the amount consumed, the plant part involved, the severity of tissue irritation, and the individual animal’s sensitivity.

All parts of Cuckoo-pint should be considered toxic. The tubers, rhizomes, roots, berries, leaves, flowers, and sap may all cause irritation. Current veterinary references describe Arum-type plants as containing calcium oxalate crystals throughout the plant, especially in rhizomes or underground storage structures. This is important because a dog digging up roots, a pig rooting in soil, or an animal chewing tuber material may receive a more intense exposure than an animal that briefly mouths a leaf.

These plants contain special cells called idioblasts. Found in a number of plant species, both poisonous and non-poisonous, idioblasts differ from neighboring cells because they contain non-living substances such as oil, latex, gum, resin, tannin, pigments, or minerals. One of these substances is raphides, or bundles of needle-like crystals of calcium oxalate that tend to be blunt at one end and sharp at the other. These crystals are packed in a gelatinous substance that contains free oxalic acid.

When animals chew on the leaves, berries, flowers, stems, tubers, rhizomes, or other parts of the plant, the tip of the idioblast is broken, allowing saliva from the animal or sap from the plant to enter the cell. This causes the gelatinous material to swell, forcing the raphides, or needle-like calcium oxalate crystals, to violently shoot out from the cells into the surrounding tissue. The calcium oxalate crystals then penetrate and embed themselves into the tissues of the mouth, tongue, throat, and stomach, causing immediate discomfort and aggravation, much as would be expected when millions of microscopic needles are lodged in the throat and mouth.

The idioblasts may continue to expel raphides for a considerable amount of time after ingestion, allowing the crystals to embed themselves not only in the mouth and throat, but also in the lining of the stomach and intestines. This can cause additional gastrointestinal upset, including gagging, vomiting or dry heaving, diarrhea, abdominal discomfort, refusal to eat, and reluctance to drink.

In addition to calcium oxalate crystals, some species may also contain proteinase or proteolytic enzymes that break proteins down into amino acids and stimulate the release of kinins and histamines. These compounds can intensify inflammation, affect blood pressure, and stimulate pain receptors. Although kinins and histamines are part of the body’s natural response to tissue damage and foreign material, the inflammatory response may worsen the irritation caused by the embedded calcium oxalate crystals.

Current veterinary and poison-control references continue to describe Cuckoo-pint as an insoluble calcium oxalate plant. Chewing or biting into the plant releases the crystals, causing tissue penetration and irritation of the mouth, oral cavity, throat, and gastrointestinal tract. Upper-airway swelling is uncommon, but possible. Because of that, most exposures are expected to be painful and irritating rather than life-threatening, but breathing difficulty, inability to swallow, or severe swelling should be treated as urgent.

In the vast majority of cases, clinical signs will present immediately or within two hours of ingestion. Clinical signs include obvious pain and irritation, generally expressed by violently shaking the head, drooling excessively, pawing at the mouth, gagging, vomiting, or dry heaving. The animal may also whine, bark, meow, or yelp in an unusually hoarse or weak-sounding voice. Other clinical signs include depression, diarrhea, inappetence, and swelling of the mouth, throat, lips, and tongue.

In some cases, swelling may be so severe as to restrict oxygen intake, resulting in dyspnea, shortness of breath, or rapid shallow gasping. This is uncommon, but any breathing difficulty should be treated as an emergency rather than a routine plant-chewing event. Irritation of the stomach and intestinal tract may also result in vomiting or diarrhea.

Because the plant is both bitter in taste and acts as an immediate irritant to the mouth, large ingestions are uncommon. Most animals will stop chewing quickly once the burning and irritation begins. If, however, a pet manages to tolerate consuming a massive amount of the plant, or eats a concentrated portion such as tuber, rhizome, or berries, clinical signs may become notably worse. Vomiting and diarrhea can severely dehydrate the animal, cause electrolyte imbalances, and send the animal into shock.

In cases involving massive ingestion of calcium-oxalate-containing plants, cardiac abnormalities, dilated pupils, convulsions, coma, renal injury, renal failure, and death have been reported. While such severe outcomes are not the ordinary expectation for Cuckoo-pint chewing exposures, they are the reason significant ingestion, airway swelling, respiratory distress, persistent vomiting, or systemic signs should be treated seriously.