Some will cause only a mild rash or itchiness, while contact with others result in more severe irritations such as facial and throat pain and swelling. This can turn fatal if the airway becomes blocked. Toxic effects of plants, however, vary greatly between species and can change according to the status of a plant's health. Several important factors should be considered here. The level and concentration of poisons in a plant can easily change not only from year to year, but throughout the growing season.
Environmental factors play a vital role throughout the year.
Unfortunately if your dog has been exposed to and poisoned by a plant, diagnosis can be difficult to pinpoint. The best way to verify diagnosis of toxic plant ingestion is often to find a specific plant physically present in the area your dog was. You need to properly identify the plant, then prove that the dog ingested it. Look for leaves or twigs that have been chewed on or near the plant itself, or collect stool or vomit samples and look for fragments there. Always bring anything you find with you to the veterinarian.