An experiment for the undergraduate quantitative analysis laboratory involving applications of visible spectrophotometry is described. Salicylate, a component found in several medications, as well as the active by-product of aspirin decomposition, is quantified. The addition of excess iron(III) to a solution of salicylate generates a deeply colored solution whose absorbance can be easily measured. The salicylate content in over-the-counter acne medications and an unknown is determined after construction of a linear calibration curve. Further, the nature of the iron-salicylate interaction can be investigated by using the method of continuous variation (Job's method) to determine the predominant stoichiometry of the complex. This experiment is easily adapted to a wide variety of available instrumentation and has been successfully tested at both the University of Michigan and Emporia State University. It is possible to complete the entire experiment in a single three-hour laboratory period, but splitting it into two sessions allows students to analyze their data as it is collected. (Contains 2 figures.)