Oscillococcinum is a homeopathic ‘medice’ (and I use the word ‘medicine’ very cautiously here) created of the heart and liver of a duck, that are incubated (read: 'left to rot') for forty days. The resultant solution is then filtered, freeze-dried, rehydrated, diluted 200 times at a ratio of 1:100 for each dilution. Which means that the amount of ‘active’ ingredients in the fluid is infinitely small. The resultant is thus effectively water. This is then impregnated into sugar tablets.
Oscillococcinum is marketed by its producer Boiron in two forms: the original formula and a children's formula called Children’s Coldcalm. It claims to ‘temporarily relieve flu-like symptoms such as run-down feeling, headache, body aches, chills and fever'.
The producer, Boiron, has halfheartedly tried to prove that Oscillococcinum can work. A review of the scientific studies performed on Oscilococcinum to date have found that the data produced in the studies are not strong enough to make a general recommendation to use Oscillococcinum for first-line treatment of influenza and influenza-like syndrome.
People should deserve some legitimate doubt or concern in considering Oscillococcinum for (the treatment of) Influenza. My advice is: get yourself vaccinated!
And if you do not trust 'Big Pharma', you should remember that Boiron is part of 'Big Quackery'. View their annual sales and net income here.
More on the cynical world of Boiron can be read here.
 FDA: Inspections, Compliance, Enforcement, and Criminal Investigations (2010). Read pdf here.
 Mathie et al: Homeopathic Oscillococcinum(®) for preventing and treating influenza and influenza-like illness in Cochrane Database of Systematic Reviews 2012
 Chirumbolo: Oscillococcinum®: Misunderstanding or biased interest? in European Journal of Internal Medicine (Letter to the Editor) - 2013