Plants are a major cause of poisoning in children under the age of 6 years. Nationally, almost 8 out of 10 plant ingestions occur in young children from US. But children are not the only victims of plant poisoning—adults, pets and farm animals can also be exposed to plants. To prevent accidents, be aware of the potential dangers of plants.The common names of plants can refer to several different species. Some may be safe and some may be dangerous. It is important to know which species you have and to check both the non-toxic plant list as well as the toxic plant list to make sure the plant you have is safe.
See full text:  The California Poison Control System – Know Your Plants (PDF)

Each situation is unique. Reactions to plants can depend on factors such as the age and size of the patient, health factors such as allergies and the amount of the exposure.Always call the poison center for up-to-the-minute treatment advice. It is essential to know the names of the plants in your house and in your yard. Keep the name tags that come with new plants attached for future identification. If your child is
being cared for at a relative’s house or daycare, it is important to know if they have dangerous plants to which your child could be exposed.
However, you must have a name of the plant (either the common name or the Latin name) to get the most reliable specific information. Poison center staff cannot identify plants over the phone from the description of the plant. There are over 1000,000 species of plants. A call to the poison center about an unknown plant described as having big shiny green leaves is not enough information to know what the plant is. If you do not know the name of the plant, take the plant or a part of the plant with leaves, berries or flowers to a reputable plant nursery for a positive identification. Try to get the common name and the Latin scientific name. Then call the California Poison Control System at 1-800-222-1222 for more help.
This is a guide to safe plants but it should not be used as a substitute for calling the poison center if a person or an animal has eaten a plant. The California Poison Control System is available 24 hours a day by calling 1-800-222-1222. If you are not in California, call 1-800-222-1222 to be connected to your nearest poison control center.
WHAT TO DO FOR A PLANT POISONING
• Do NOT induce vomiting.
• Remove any plant parts from the mouth or hands.
• Wash around the mouth and hands and give a few sips of water.
• Check for any irritation of the skin, mouth or tongue.
• Call the California Poison Control System at 1-800-222-1222
• Even if you are not sure, call the poison center for help. It will not be as waste of
time.
• Do not wait for symptoms to appear. Treatment will be more difficult once
symptoms have developed.
• If you are advised to go to the hospital, take the plant or part of the plant with you.