There is no reason to consider the Vinca major poisonous. Catharanthus rosea (formerly Vinca rosea), the Madagascar periwinkle, does contain a group of alkaloids including vinchristine and vinblastine both of which are used in chemotherapy. Chemotherapy is, of course, controlled poisoning.
Correspondingly, how poisonous is Morning Glory?
The Morning Glory is a beautiful, flowering climbing vine (although a shrub variety is also available). While not all species are poisonous, some may cause significant signs when large amounts of seeds are ingested. The seeds from the flowers of some species contain the toxin, lysergic alkaloids.
Is Clematis toxic to humans?
Rather mild but toxic, clematis is poisonous. When touched or consumed, the toxin called anemonin (irritant glycoside) affects the pets and humans both. It can cause dermatitis in some people after contact and mild burning sensation and ulcer in mouth, if eaten.