There are many cases of smelling disorders, which can impact an individual’s ability to smell. In addition, it’s important to understand there is a whole population among us who cannot smell (anosmia), who may have grown up never smelling (congenital anosmia), or who have reduced smell (hyposmia). Because the sense of smell is not as severe, life-threatening, or well-known, it is not widely studied. With the lack of research in this field, people with smell disorders have few treatment options. While there is some research on anosmia, the understanding of anosmia has plateaued, with many articles re-visiting known causes and common evaluation methods. More in-depth knowledge, however, is known only to a handful of researchers or specialized doctors. This literature review will discuss the research on anosmia, covering causes and effects of anosmia, with some discussion of physiology. This paper will also analyze relevant research that may point to potential treatments, touching on olfactory dysfunctions that may help us to understand anosmia.