In the 21st century, which is often characterized by fake news and pseudoscientific claims, it is important that students should engage with the tenets of science, and how it differs from pseudoscience. The Rationality Index for Plant Use (RIPU) tool, introduced in this article, could be used in a problem-based and cooperative learning activity, where students explore the tenets of respectively science and pseudoscience. During such a learning activity, students will engage with scientific literature to either find support for hypotheses, or to nullify it. The activity also holds affordances to sensitize students toward the processes of science and the realization that scientists publish their findings in high-quality, peer-reviewed journals.