Oscillococcinum is believed by homeopathic practitioners to act under one of the main principles of homeopathy--"like treats like."  This general rule is applied under the belief that extremely high dilution of a substance that causes disease will help one's body cure the disease.  These beliefs originate from the tenets of the "father of homeopathy", Samuel Hahnemann (1775-1843).  Hahnemann believed there are not specific causes of disease, but rather disease is a "disturbance of life force." 

During the Spanish flu epidemic of the early 1900s, a French physician named Joseph Roy (1891-1978) was on military duty and studied the blood of victims of the flu.  Using microscopes, he saw organisms he believed to be bacteria consisting of two unequal balls that vibrated very quickly.  He called them "oscillococci."  He stated that they could vary significantly in size, at times becoming so small that he could not observe them with a microscope.  With further observation, he stated that he also found these organisms in the blood and tumors of cancer patients, syphilitic ulcers, tuberculosis patients, gonorrhea patients, as well as people who had eczema, rheumatoid arthritis, mumps, measles, and chicken pox.  He believed he had found a "universal germ".  No other bacteriologist has ever seen what Roy saw, and it is unknown what exactly it was that he described as "oscillococci." 

Roy, however, immediately thought of homeopathy.  He took the teachings of Hahnemann, and used the ground up liver and heart from a muscovy duck as the "active ingredient."  He chose these organs because, "The Ancients considered the liver as the seat of suffering, even more important than the heart, which is a very profound insight, because it is on the level of the liver that the pathological modifications of the blood happen, and also there the quality of the energy of our heart muscle changes in a durable manner" (Nienhuys 2).

Under the teachings of Semyon Korsakov (1788-1853), homeopathic remedies are commonly diluted by placing the "active ingredient" into a test tube and filling the test tube with sugar water, alcohol or a combination of the two.  After shaking the test tube and allowing the mixture to sit for awhile (40 days in the case of oscillococcinum), the liquid is poured off with only the droplets sticking to the sides of the glass remaining.  When the tube is refilled, the dilution factor is assumed to be 1:100.  Each one of these 1:100 dilution steps is known as a Korsakov, after the inventor of this dilution method.  Oscillococcinum is prepared to a dilution of 200 Korsakov.