Pros: It won't ordinarily damage anything except the pocketbook.
Cons: It's nothing but an elaborate confidence trick.
If the butcher were to stamp on his kiszka the advice Boiron puts on its "Oscillococcinum"--"Take at the first sign of flu"--it would be an infinitely sounder recommendation. Blood sausage contains a bit of iron; fry it up with some eggs and wash it down with a glass of orange juice, and one has had a vitamin-laden, hearty, and fattening meal. Oscillococcinum, on the other hand, has all the nutrition of a Tic-Tac, at over a hundred times the cost, and has no medicinally active fraction.
There's a caveat to this, however: Oscillococcinum is dressed up to look like medicine, in a box of the same dimensions used for (e.g.) Sudafed, its tablets dutifully packed into plastic tubes, with clinical-sounding directions printed on the back. Not unlike the obscurity of the terms used on a real medicine box--not even the best-trained chemist can tell from the name what "Ibuprofen" is--Boiron calls water "Anas Barbariae Hepatis et Cordis Extractum 200CK HPUS". (That's kind of catchy, even chantable: Anas Barbariae Hepatis et Cordis/Anas Barbariae Hepatis et Cordis/Or Mumbo-Jumbo, God of the Congo,/And all of the other/Gods of the Congo,/Mumbo-Jumbo will hoodoo you...) Oscillococcinum is dressed up enough that silly people will think it is medicine and either experience a slight placebo effect or ascribe their natural recovery to the product.
So that you will not be a silly person, I will tell you in plain terms what Oscillococcinum is: a 100 mg, one-dose tube of round 5 milligram tablets consisting of 85% sucrose and 15% lactose, moistened with some water. Giving sucrose-lactose tablets a fancy fifteen-letter name can no more turn them into influenza medication than writing "Soylent Green" on a cracker box can turn Saltines into people.
There's a sort of belief in magic involved here, quite similar to the fraud underlying homeopathy: the water used to moisten the sugar tablets is the 200th rinse of a vessel that previously held the rotten liver and heart of a Muscovy duck. (I couldn't make that one up if I tried.) Although the pseudo-latin name for the preparaton refers to "Anas"--the generic name for teals and mallards--the "Homeopathic Pharmacopeia" to which the letters HPUS refers calls for the tropical Muscovy duck.
35 grams of the duck's liver and 15 grams of the heart--what lovely precision, and what nice round numbers!--are put into a one liter, sterile glass vessel that is topped off with a standardized mixture of glucose and pancreatic juice, and left to sit and autolyze for forty days. After forty days, the slime and gunk are poured out, and the bottle is filled with water, agitated, and poured out again. This rinsing process--denoted by the "K" in Boiron's fancy name for water--is repeated 200 times, and the water from the 200th rinse is used to prepare the tablets.
The "C" in the name refers to a (generous) assumption that one percent of the previous rinse stays behind each time the solution is poured out. This means that the water is an aqueous solution containing a 1 in 100 to the 200th power (that's one in ten to the four hundredth power, or one in a googol to the fourth power) fraction of the original duck heart/liver/pancreatic juice/glucose solution.
Let's make another generous assumption, taking the original duck heart and liver to be made up of carbon atoms. There are 4.17 moles of these atoms in the original 50 grams of liver and heart, meaning that there are about 2.5 times ten to the 23rd power atoms present. Threre is a one in 2.5 times ten to the 377th chance that one of these atoms is in that final rinse water. Consider that the autolyzed gunk is made up of molecules heavier on average than a carbon atom, and the odds that the final rinse contains one such molecule decrease by a factor somewhere between 10 and 1000; be generous and say that maybe some of that glucose or pancreatic juice ends up being some active molecule and the odds go up by no more than a factor of ten. Comparing these odds to the chance that your lungs now contain a nitrogen molecule breathed by Mohammed is instructive.
Saying that there's no evidence that Oscillococcinum is anything more than a placebo is not strong enough. Saying that we have no reason to believe it is more than a placebo is not strong enough. Speaking as a biophysicist, I'll put it as follows: if Oscillococcinum, prepared as claimed by its maker, is anything other than water and sugar, or if (as claimed by some of its true believers) the rinse water is imparted with some special property by the autolyzed duck parts, then everything we think we know about statistical mechanics, the foundation for much of modern science, is completely wrong.
Along with the related homeopathy, Oscillococcinum is perhaps the only medical fraud actually protected by law in the USA; the products need not be proven effective in treating the conditions they are claimed by their packaging to treat, provided that the claims pertain only to self-limiting diseases. (I say "fraud" because no reasonable person, on learning what this product is, should even suspect that it can treat or prevent influenza.) Contrast this with herbal remedies (like valerian root) known to be effective but for which nobody wants to pay for FDA trials: such products must, often farcically, be labeled as not claiming to cure, prevent, or treat any disease. Treatments for non-self-limiting diseases must be prescribed by homeopathic "doctors" specifically trained in the confidence game. Influenza isn't always self-limiting, and can be crippling or lethal, yet somehow Oscillococcinum slips by.
I hope that wishful, magical thinking centered on Oscillococcinum is not preventing people with severe flu from seeking real treatment. Don't waste your money on these sugar tablets. Yearly immunization is the best preventative measure, and if you find yourself or someone you are caring for showing heart arrhythmias, difficulty breathing, very high fever, or signs of secondary infection such as pneumonia, seek medical attention.
This is the first entry in the Tarred and Feathered Write-Off.