Larry Marks was developed as part of a multi-station, standardized patient assessment. The student's performance is measured by checklists filled out by the standardized patient and by the evaluation of responses to written questions on the interstation exercise. This patient is a 65 year-old carpenter who presents to the outpatient clinic with a 3-week history of hard small stools, bloating, and crampy abdominal pain. On examination he has lower abdominal tenderness. The examinee's task is to take a focused history and perform a focused physical examination. A complete set of student instructions, checklists, standardized patient training materials, written exercises and a grading key are included. The associated documents are available to faculty members only.