Dogs, especially puppies, have a bad habit of chewing on all sorts of things that don't belong in their mouth, including plants such as passiflora vine, which is also known as passion vine. While some animals are good at discerning whether or not a plant is poisonous, dogs are indiscriminate, and will munch on the leaves of a poisonous plant just as readily as a non-toxic one.
Toxicity
Passiflora is considered non-toxic to dogs as well as humans and other animals. Eating small amounts of this plant will not poison your dog. Some dogs have sensitive digestive systems, however, and may have an upset stomach if they eat very much of a passiflora vine. If your dog becomes ill after eating or chewing on a plant, contact your veterinarian or a pet poison hotline. Mild vomiting after eating a non-toxic plant is not serious, however, vomiting is one sign of poisoning, and is often seen in conjunction with drooling, diarrhea, lethargy, pale gums and an increased heart rate. Although passiflora vine is not toxic, it is possible for your dog to ingest toxic plants that may be growing in close proximity to the vine.