The Internet promotes computer-mediated communications, and asynchronous learning network systems permit more flexibility in time, space, and interaction than the synchronous mode of learning. The key point of asynchronous learning is the materials for web-aided teaching and the flow of knowledge. This research focuses on improving online interaction by using labeled postings embedded in the e-Forum discussion tool developed for this research. Subjects for the study were students who enrolled in the "Drug and Nutrient Interaction" course using the Problem-Based Learning (PBL) approach. Students' online discussion data were gathered during the academic years of 2004 and 2006. Data from the study reveal that the design of labels for postings promoted interactive responses among learners, and the frequency of personal discussion increased. Self-improvement and the development of new subjects from discussion forums were also observed among learners.