Here's the situation: my main character is being held captive out it the countryside by a group of bandits. In order to escape she needs to incapacitate them, and has the opportunity to introduce something into the food they are cooking. She (unlike her creator) has extensive knowledge of herbs. What could she find around that would take them out so they would be unable to pursue her? I'm thinking of a laxative/emetic rather than fatal poison. Time of year - early summer.