—With the development of improved and cost-effective technologies, it is now possible to detect thousands of metabolites in biofluids or specific organs, and reliably quantify their amounts. Metabolomics focuses on studying the concentrations of metabolites in a cell or a tissue. In this paper, we describe a prototype web-based metabolomics data analysis system, PathCaseMAW (PathCase Metabolomics Analysis Workbench), which features (1) A web-accessible metabolic pathway database that supports online browsing and querying, and is novel in that it includes tissue and subcompartment information for pathways, and models transport processes, (2) Tissue-aware visualization support for viewing processes, pathways, or groups of pathways in PathCaseMAW database, and (3) An online metabolomics data analysis tool, called Automated Consequence Prediction Tool, which allows users to upload their own observed/measured metabolite level changes, and computationally invalidates or M(aybe)-validates t...