All parts of common columbine, including the stem, leaves, flowers, and seeds, are toxic when they are ingested raw. Contact with the plant's sap may also lead to dermatitis (skin irritation and inflammation). The symptoms from common columbine poisoning are likely to cause only mild to moderate effects, but the symptoms are not well-known, since there are few documented cases of it. Adverse effects are most likely to occur from accidental ingestion.

In pop culture, poison ivy is a symbol of an obnoxious weed because, despite its unthreatening looks, it gives a highly unpleasant contact rash to the unfortunate person who touches it. Still, it is commonly eaten by many animals, and the seeds are a favorite with birds. The leaves turn bright red in fall. Its sister species, Western poison ivy (Toxicodendron rydbergii), is not considered to be invasive in the United States, but is noxious in Australia and New Zealand.

If either ingested or touched, dieffenbachia can cause negative reactions. The symptoms range from moderate to severe and can be dangerous if airways are blocked. Due to the calcium oxalate contained in this plant, its leaves and sap have toxic properties. When ingested, they can induce symptoms such as lip and tongue swelling, drooling, speech loss, and difficulty breathing; when touched, they can cause a painful skin rash or eye irritation. Since these plants are often found indoors as decorative plants, be careful when keeping them around small children. Always wear gloves when handling this plant.

True to this plant's reputation, consumption of black nightshade can be extremely toxic to dogs, and warrants immediate veterinary attention. All parts of these plants contain several toxic substances which can cause loss of appetite, excessive drooling, vomiting, diarrhea, dilated pupils, confusion, behavioral changes, and weakness. In more severe cases, difficulty breathing, a lowered heart rate, coma, or even death may occur, so treat it as a medical emergency if your pet has come into contact with this plant.

Although its berries look juicy and tempting, the fruits and the root of pokeweed are toxic and should not be eaten. Pokeweed is considered a pest species by farmers but is nevertheless often grown as an ornamental plant. Its berries can be made into pokeberry ink as well.

Bird of paradise is generally considered non-toxic but can be poisonous when ingested in large quantities. Cases of poisoning are typically mild to moderate with symptoms including abdominal cramps, nausea, vomiting, and diarrhea. Cases of poisoning may be more serious in children. The fruit and seeds are considered to be the most toxic parts of the plant. The frequent use of this plant as a houseplant could be a factor in poisoning frequency. This plant can be mistaken for another more toxic species, Poinciana gilliesii, as they share the same common name, bird of paradise.

Bearded iris is known to cause contact dermatitis in some individuals. The most commonly reported symptom is minor skin irritation, typically lasting only a few minutes. This can result from contact with the seeds, roots, or sap of this plant. Furthermore, all parts of bearded iris are toxic when ingested, especially the roots. Symptoms typically including minor or moderate burning sensations, nausea, vomiting, abdominal pain, diarrhea, and fever. This plant is most often encountered in a garden context, where it is planted as an ornamental.

True to this plant's reputation, consumption of potato can be extremely toxic to dogs, and warrants immediate veterinary attention. All parts of these plants contain several toxic substances which can cause loss of appetite, excessive drooling, vomiting, diarrhea, dilated pupils, confusion, behavioral changes, and weakness. In more severe cases, difficulty breathing, a lowered heart rate, coma, or even death may occur, so treat it as a medical emergency if your pet has come into contact with this plant.

Smoketree is a deciduous tree native to Southern Europe and Central China. The flowers of the smoketree are pinkish-purple and long-lasting. They grow in clusters along branches and give a smoky appearance to the tree when in bloom. In China, they are used as important fall decorations due to their foliage turn bright red in the fall.

Creeping buttercup can be severely toxic to dogs; you should seek immediate veterinary attention if you believe your dog has eaten or come into contact with a plant of this type. All parts of these plants contain ranunculin, a toxin that is poisonous when swallowed and also can irritate skin, causing redness or itch. Ingestion symptoms ranging from excessive drooling, vomiting, diarrhea, weakness, and loss of appetite to paralysis, seizures, jaundice, spasms, collapse, or even death.

American elder (Sambucus canadensis) is a North American native deciduous shrub with enormous inflorescence of grouped small white flowers and dangling bunches of mauveine berries. When cooked, the fruits can be added to pies, pancakes, and jellies. Wine can also be produced from its flowers and fruits. The bushy leaves and arching branches attract wildlife, providing nesting space for birds.

Hyacinthus orientalis is one of the heralds of spring. The name common hyacinth comes from the Greek name Hyacinthus. According to Greek legend, Hyacinthus was admired by both Apollo and Zephyrus. Hyacinthus ended up being killed out of jealousy and a flower bloomed on the spot where his blood was spilled. Apollo named the flower after his lost love.

Clematis virginiana species are mildly to moderately toxic to dogs. All parts of most devil's darning needles plants contain a strong irritant that, if eaten, causes excessive salivation and loss of appetite. This may progress to vomiting or diarrhea. More severe symptoms are possible but very rare, as these plants tend to be extremely distasteful to dogs, and so it's not often eaten in large quantities. Seek veterinary attention if your dog is experiencing the stronger symptoms.

Canada yew is highly toxic to all animal species, including humans, dogs, cats, livestock and poultry, with all parts of the plant capable of causing death when consumed in large amounts.

Rough horsetail (Equisetum hyemale) is an evergreen perennial. An aggressive grower, it reproduces through spores and is non-flowering. It prefers full sun to partial shade and is pest resistant. It provides erosion control, grows well in wetlands and makes an interesting addition to water gardens. Expected height of 61 to 91 cm.

Wild daffodils have low-level toxicity when the leaves or bulbs are ingested. The bulbs, however, are the most toxic part of the plant. If the bulbs are ingested, symptoms may include vomiting, diarrhea, and excessive salivation. If a large quantity is consumed, convulsions, low blood pressure, tremors, and cardiac arrhythmias may occur. Poisoning is most likely to occur from accidental ingestion by children, as wild daffodils are grown in gardens around the world.

Striped barbados lily is perennial herbs with showy flowers but it contains toxic compounds, most notably alkaloids lycorine and tazetine, as well as calcium oxalate crystals.

Durian (Durio zibethinus) is a tropical plant from Southeast Asia. It bears large, spiny, edible fruit which has become a major export crop of the region. The fruit is best known for its pungent smell, which provokes opposing reactions, ranging from near-addiction to revulsion. In some areas, it has even been banned from public transport and hotels.

All parts of the persian cyclamen contain toxins that are extremely hazardous to dogs, with the highest concentration in their tubers. Use caution if your dog is in a yard where persian cyclamen is found, especially if they enjoy digging. Symptoms range from lethargy to coma, and immediate veterinary care is needed to pump the canine's stomach to void the body of the toxin.

The heart of jesus plant has a name that implies purity, but it is actually toxic. Like other Caladiums, its sap is extremely irritating when eaten or even just applied to the skin. A painful, itchy rash breaks out on contact. That rash is essentially what a person who ingests it will experience as well, except inside of their mouths and all the way down their digestive tracts. Besides a great deal of pain and irritation, this causes severe nausea, excessive salivation, vomiting and diarrhea, and also significant swelling in many cases. Keep this plant away from children.