Malariotherapy is a medical procedure that uses the malaria parasite to treat other diseases such as syphilis and neurosyphilis. The use of the term "malariotherapy" has declined over time due to ethical concerns surrounding the use of infectious agents for medical treatments. Other terms used to describe this medical procedure include "malaria innoculation," "malariatherapy," and "malaria treatment." These synonyms reflect the historical progression of the use of malaria to treat syphilis, from an experimental and controversial medical procedure to an outdated and unethical practice. Despite its effectiveness in treating syphilis, the potential harm to the patient and ethical considerations make its use impractical in modern medicine.