Any irritation in the stomach will result in emetic (vomiting) activity in dogs. (dog-health-handbook.com)
Persistent vomiting is a big problem to address in infected dogs, thus anti emetic drugs (anti-vomiting), such as metaclopramide should be added at 2 mg / Kg B.W in infusion. (dog-health-handbook.com)
These flowers found in the genus Narcissus contain lycorine, an alkaloid with strong emetic properties (something that triggers vomiting). (statecollegevethosp.com)