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.

All parts of the evergreen spindle are considered toxic if ingested in large quantities. Symptoms can range from mild to life-threatening including vomiting, weakness, diarrhea, chills, convulsions, and coma. Since these plants are commonly used as ornamental hedges, you should be mindful of any children who may encounter the plant, be attracted by its colorful leaves and flowers, and may be tempted to eat them.

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.

True to this plant's reputation, consumption of jerusalem cherry 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.

Sun spurge (Euphorbia helioscopia) is a winter annual that grows along the ground in a variety of locations from gardens to wastelands. It features distinctive red colored stems with toothed leaves that emit a toxic milky sap when cut or torn. Pale yellow flowers bloom from spring to summer and give way to fruit. This plant is considered a weed.

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.

Regal crowns of flowers perch atop tall stems of the crown imperial, or Fritillaria imperialis. Bulbs can be planted in mass plantings, flowerbeds, and container gardens. These striking flowers grow from bulbs and bloom in early spring. The skunk-like fragrance is a great pest repellent.

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.

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.

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.

Starch grape hyacinth (Muscari neglectum) is a perennial plant native to Eurasia, commonly grown as an ornamental houseplant in temperate climates. It is also known as the common grape hyacinth or the grape hyacinth for its flowers' resemblance to the grapes.

Slender false garlic (Nothoscordum gracile) is a herbaceous perennial that will grow to 51 cm tall. It blooms from spring to summer with clusters of small white flowers with purple stripes and colorful green and gold stamens. Flowers bloom at the top of the stem. Considered a weed it is commonly found growing along sandy roadsides and woods. Attracts bees and other pollinators.

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.

Apple of Sodom, or Calotropis procera, is an extremely poisonous plant. The fruit of this plant ripens and bursts, causing the seeds to scatter. In Jamaica, the fibers inside of the fruit are collected and used to stuff pillows.

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.

Spineless butcher's-broom (Ruscus hypophyllum) is an evergreen shrub that is native to the Mediterranian region. It expands through a creeping root system, allowing it to become a widespread groundcover plant in just a few growing seasons. The flowers are unremarkable and will only on rare occasions fully mature into small red berries.

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.

Coffee senna (*Senna occidentalis*) is a perennial shrub that prefers warm and humid environments. It is sometimes considered an invasive weed that grows in open woodlands, waste areas, and roadsides. It blooms in spring with yellow flowers, followed by brown fruit in late summer and early fall. Seeds can be used as a coffee substitute, although it does not contain caffeine.

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.