In this chapter, two of the four patients experience digestive issues. A team of doctors will run tests on the digestive by-products of these two patients, while the students will be expected to formulate an even deeper hypothesis about the conditions of the two patients, based on their symptoms. This Teacher Guide chapter highlights the Before the Lesson, During the Lesson, and After the Lesson instructions and recommends that the teacher read prior to starting the lesson. To learn more about the Student Edition chapter referenced here, check out “Let’s Diagnose Them, Lab 2: Digestive By-Products and Body Mass Index Analysis.”