The present disclosure is directed to systems and methods for identifying unknown drug targets via adverse event data. An analyzer receives an identification of a first drug having one or more unknown target proteins and identifies a second drug related to the first drug. The analyzer retrieves, from an adverse event database, a first side effect profile associated with the first drug, and a second side effect profile associated with the second drug. The analyzer generates a third side effect profile comprising a subset of the first side effect profile not shared by the second side effect profile, and identifies a third drug having a fourth side effect profile comprising the third side effect profile. The analyzer retrieves a list of one or more target proteins of the third drug not targeted by the second drug, and presents the retrieved list as potential target proteins of the first drug.