Every part of an oleander plant, including the leaves, stems and blooms, is toxic to dogs. Eating these plants can be deadly, but it doesn't have to be if your dog gets veterinary treatment as soon as he shows any symptoms of poisoning.
The first sign of oleander poisoning often is vomiting. Others are drooling, tremors and seizures. Some dogs will have diarrhea. In serious cases, your dog may collapse or have seizures. Lack of appetite is another symptom of poisoning, but it may take a day or two to become apparent. The severity of symptoms depends on the size and health of the dog and how much oleander the dog has chewed or consumed.
The most serious symptoms of oleander poisoning are not readily obvious -- cardiac arrhythmias, or a disrupted heartbeat rhythm, and abnormal heart rate. A high potassium level, which can be detected only through testing at a veterinary clinic, is another symptom. Your dog may also have irritated gums from chewing on the oleander, which can go unnoticed except upon close examination.
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