By Jason Wyrwicz. President of Pots, Planters & More.

Dogs and cats are many things to many people —a best friend, a companion, a family member. And, in the cases of many plants that are growing within the walls of our homes, and even outside in our gardens, our pets could be in danger.

Your favorite household plants could be harming your cat or dog, evidenced by calls to the American Society for the Prevention of Cruelty to Animals (ASPCA) Poison Control hotline . It receives approximately 150,000 calls annually from pet owners seeking help with accidental poisonings. About a quarter of all pets poisoned by non-drug products are poisoned by plants.

Based on a list of toxic plants from UC Davis School of Veterinary Medicine’s most common causes of emergency calls and Texas A&M ’s “Common Poisonous Plants and Plant Parts, ” we’ve compiled a toxic plants guide, breaking down the risks to your cat and/or dog and warning signs to look out for.

Depending on how a particular substance affects your dog ’s or cat ’s body and how much of the plant was ingested or inhaled, pet poisoning symptoms can range from vomiting to death. So, when buying plants for your home, opt for those that won ’t cause problems if Fido decides to take a nibble. Both indoor and outdoor plants can cause harm, and we ’ve narrowed down the list of 12 plants that are common and/or deadly. The list is broken into three categories of where you would find the plant: garden and wildflowers; trees and shrubs; or indoor house plants. For indoor plants, a planter box can be a useful tool, keeping the plants out of the way from your pets.

The most poisonous plant in the world, according to Guinness World Records, is the Castor Bean. This can be both a house and outdoor plant whose beans contain Ricin, a highly toxic component that inhibits protein synthesis. Toxic to both cats and dogs, clinical signs of distress can include anything from oral irritation to kidney failure to death.

Second in line on the toxicity scale is Caladium. Also a house and outdoor plant, 13 percent of toxic plant exposures in pets were due to Caladium. Clinical signs of toxicity include excessive drooling, vomiting and difficulty breathing and swallowing. Caladium also gives humans issues, being the fourth most commonly reported plant toxin exposure in humans.

Rounding out the top three are Lilies, while beautiful, may be harmful to your feline. The mortality rate has been reported as high as 100 percent with Lily toxicity if left untreated or treated later than 18 hours after exposure. Lilies are the most common plant for pet poisoning, and eating small amounts of any part of this plant can cause dangerous symptoms and lead to death from kidney failure.

Dumbcane, Rosary Pea, Larkspur, Foxglove, Autumn Crocus, Sago Palm, Black Locust, Yew and Oleander finished out the top 12 as having toxic effects on both dogs and cats. Particularly scary are the plants that grow in the wild, such as the Black Locust and the Yew. The fatality rate from Black Locust exposure is one out of every 10 exposures. Death often is the first indication of Yew toxicosis, with all parts of the plant being toxic except for the berries. A dog could consume a potentially lethal dose simply doing what he or she does best —while playing with taxus species branches or sticks.

Nine out of 10 poisonings happen while the pet is home, but the best course of action is to pick your plants wisely, place them in a tall planter where they can not easily be accessed by furry friends, and keep an eye on things while playing outdoors. Man's Best Friend will thank you.