Although some optical spectroscopy methods were introduced more than ten decades ago, they are still finding new applications in many areas of science. Specifically, medicine and biology are two areas of research where optical methods may facilitate and improve the study and characterization of tissue and biological molecules in order to improve medical diagnosis. Optical spectroscopy can aid in the study and detection of some diseases faster than standard laboratory techniques. This work demonstrates applications of Micro-Raman spectroscopy and multivariate analysis to biomedical problems such as: breast cancer detection, toxoplasmosis study through indirect antibody detection, and discrimination between antibody isotypes (IgG and IgM)