Numerous chemical options are available for addressing excessive water and gas production problems. The chemistry of most of these options is complicated. A petroleum engineer with an average chemistry background has difficulties understanding these to a level that enables him/her to choose and apply a proper option to the problem at hand. In this paper, we provide a brief overview of all chemical water/gas shutoff (WGSO) options available to date. Monomer systems, polymer gels, relative permeability modifying polymers, inorganic gels, plastics etc. are commonly used chemical options. Less common options include viscous flooding, selective plugging with induced mineral precipitation and other miscellaneous grouting materials. Pros and cons of all these options are also discussed.