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.

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.

Golden dewdrops (Duranta erecta) is an ornamental sprawling shrub commonly found in subtropical and tropical gardens all over the world. Its gentle purple blossoms are often visited by butterflies and hummingbirds. Golden dewdrops is considered a weed in Australia, South Africa and certain parts of East Asia.

Oleander is moderately to highly toxic to humans – instances of ingestion, or physical contact with this plant's sap, should be immediately addressed by medical professionals. While fatal cases of oleander poisoning are very rare, they are possible. All parts of this plant are toxic if ingested. Physical contact with the plant's sap, which is found throughout the plant and is more likely to be exposed if the plant is cut or damaged, may cause dermatological symptoms, including redness and itchiness of the skin. Symptoms following ingestion include low blood pressure, lethargy, an irregular heartbeat, blurred vision, confusion, diarrhea, vomiting, dizziness, fainting and, in extreme cases, death. Be mindful of curious children, as oleanders are an extremely common ornamental plant cultivated in gardens and parks around the world.

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.

Sprenger's asparagus fern (Asparagus aethiopicus) is a fern species native to South Africa. Despite its common name, this plant is not a true fern by taxonomy. Sprenger's asparagus fern is generally considered to be an invasive species. The common name was established by Carl Ludwig Sprenger who popularized cultivating sprenger's asparagus fern as an ornamental plant.

Devil's-backbone (Euphorbia tithymaloides) is a succulent species of spurge native to North and Central America. It has been planted in gardens since the 17th century and valued for its unique appearance and its habit of attracting hummingbirds. However, nearly all parts of this species are toxic and should not be consumed.

A hardy, heavy vine, the cup of gold vine needs a sturdy structure to grow on and show off its 15 cm yellow blooms. These flowers have a fragrance similar to the sweet scent of bananas. This vine can grow up to 15 m long, or it can be pruned into more of a shrub shape.

Asthma-plant (Euphorbia hirta) is a ground-hugging spurge weed whose branches can grow to 61 cm long. It blooms from summer through early fall, dying off after the first frost. A milky sap will seep from broken stems or leaves. It can be a nuisance weed that reproduces rapidly.

The castor bean is important for its oil which is used as a lubricant, biodiesel ingredient, and rodent repellent, among other applications. The plants are now commercially planted globally, with India producing nearly 75% of the world's castor oil. Castor beans cannot be eaten because they contain a potent poison that's released if the seed is broken.

The barbados nut (Jatropha curcas) plant is cultivated throughout the world for ornamental uses because of its rapid growth. Since cattle will not consume the leaves, it works very well as a living fence around grazing areas. Oil is extracted from the nuts and used as a torch fuel and burns so well that the fires are not affected by strong winds!

Argemone mexicana has been naturalized in many parts of the world. It is extremely tolerant of drought and poor soil, but is poisonous to grazing animals. Its seed pods secrete a pale yellow latex when cut open. In India, the mexican prickly poppy is used in the Holika Dahan festival, in which adults and children worship by offering flowers.

A fast-growing succulent, donkey ears has waxy, ear-like leaves that can grow up to 52 cm long. New plants grow on the tips of the leaves. When the leaves reach the soil, they will take root and form new plants.

True to this plant's reputation, consumption of turkey berry 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.

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.

The crown Flower has beautiful flowers that are used to make leis and were a favorite of the last queen of Hawaii. The outer petals of this flower curl back, and reveal what looks like a crown inside. The sap of this plant may cause skin irritation and can be considered toxic.

Palay rubbervine (Cryptostegia grandiflora) is a plant species that can grow to be 2 m tall when the plant is a shrub. When palay rubbervine is supported by other vegetation as a vine, it can reach up to 30 m in length. This species is native to Madagascar.

Many species within the Cycas revoluta genus are highly toxic to dogs - if you suspect your dog has ingested any part of a sago palm plant, you should contact a vet immediately. The Sago palm is a very common ornamental and is the most common culprit. These plants contain high concentrations of the cycasin toxin, which is found throughout their structures but is most concentrated in their seeds. Ingesting even a small amount of cycasin can cause vomiting and diarrhea. Larger amounts can cause damage to the intestines and liver, coma, or death.

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.

Glossy shower (Senna surattensis) is an evergreen, perennial tree that blooms year-round with golden-yellow flowers. It is also called Scrambled Eggplant, Sunshine Tree, or Golden Senna. It thrives in full sun and prefers well-drained soil. It is considered an invasive weed in Asia.