In today’s modern technogenic world, forming an ecological consciousness, perception and thinking among schoolchildren is a vital task. Knowledge of chemical toxicology is essential for students of all ages to help protect and maintain a healthy environment. Given that toxicology is characterized by an increased level of complexity, the purpose of this work was to develop and apply gaming methods in teaching the basics of chemical toxicology as part of environmental education of schoolchildren. We developed and implemented a training lesson for schoolchildren called “Fascinating phytotoxicology” for secondary school students, which consists of several stages. At the first stage, when using explanatory and illustrative methods in teaching, students received theoretical knowledge of phytotoxicology; at the second stage, students enhanced their knowledge in a playful way by solving situational problems composed by us, guessing riddles and answering intriguing questions; at the third stage, a survey was conducted among schoolchildren to identify the students’ level of interest in the topic and how much of the material was assimilated. The survey showed that the implementation of this gaming teaching method allowed students to learn complex material better, increased the activity and interest of students, and also contributed to the formation of an ecological awareness and environmental responsibility.