Chusig, an indigenous Ecuadorian who had to change his name to Eugenio Espejo to study medicine, discovered that many diseases were caused by microorganisms long before Pasteur's discoveries.

Doctor Pedro Leiva revealed that the cure for malaria was contained in the bark of the cinchona tree.

[2] The hospital also operated as a hospice, maternity clinic, and pediatric center, also nursing people with sexually transmitted infections and skin diseases.

Patients were attended by "herbalists, shamans, healers, doctors, barbers, blood letters, Sisters of Charity, nurses, technologists, social workers and friars".

[3] San Juan de Dios Hospital closed its doors in 1974 after 409 years of continuous service.