Bioactive natural products have formed the core of most ancient systems of healthcare and medicine. Crude natural preparations have been used for relief in a variety of infections and disease conditions. This review starts with a general description of the bioactive natural products, followed by the information on natural products being used for dealing with infectious microorganisms. In the latter section, much emphasis has been on the natural products capable of disrupting microbial communication, i.e., quorum sensing. Quorum sensing inhibitors are being expected to emerge as an important class of novel therapeutic agents in the future. Few other issues, important while performing lab experiments with natural products, are also touched upon.