Serotherapy is a medical term that refers to the use of serum to treat diseases. Although it is a specific term, there are several different synonyms for serotherapy that can be used interchangeably. One synonym is immunotherapy, which refers specifically to the treatment of diseases through the immune system. Another synonym is serum therapy, which is more specific to the use of serum in the treatment of diseases. Other synonyms include antibody therapy, antiserum therapy, and plasma therapy. These terms can be used interchangeably depending on the context and specific treatment being discussed, but all refer to the broad umbrella of using serum to treat diseases.