Marijuana

Symptoms include depression of the central nervous system and loss of coordination, diarrhea, vomiting, drooling, increased heart rate, seizures and coma.

Azalea / Rhododendron

Vomiting, drooling, diarrhea, weakness and depression of the central nervous system.  Severe poisoning can lead to coma and death from cardiovascular collapse

Sago Palm

Symptoms include vomiting, diarrhea, seizures and liver failure.  Though all parts of the plant are poisonous, the seeds pose the most hazard

Oleander

Gastrointestinal tract irritation, abnormal heart function, hypothermia and death

Lilies

Severe kidney damage

Castor Bean

Severe abdominal pain, drooling, vomiting, diarrhea, excessive thirst, weakness, loss of appetite - severe cases can result in dehydration, muscle twitching, tremors, seizures, coma and death

Tulip / Narcissus Bulbs

Intense gastrointestinal irritation, drooling, loss of appetite, depression of the central nervous system, convulsions and cardiac abnormalties

Cyclamen

Gatrointestinal irritation, intense vomiting and even death

Kalanchoe

Gastrointestinal irritation and arrhythmia

Yew / Japanese Yew

Trembling, loss of coordination, difficulty breathing, gastrointestinal irritation and cardiac failure