For some readers, this might be the most useful post I’ve ever written. But first; some history. Back in grad school, I was dating a Cliffie. We were out to dinner at a nice (and cheap) restaurant in Cambridge. I’d had the flu and probably should have canceled, but in your early 20s, libido conquers all. So we’re sitting there, and I began to feel really nauseous and said we should pack it in, and I should go home.
She said “Let me try this, my father’s a General Practitioner”. So she ordered a can of coke, opened it and let it sit for a while till it warmed up and the fizz was gone. Then she told me to drink it in slow, small sips. It worked ! The nausea vanished and we continued on.
Fast forward to last night and probable food poisoning (or severe flu). No Coke in the house, but as soon as my wife got to a store opening at 7 this AM, it worked again — no nausea and stomach distress within a few minutes (I’d vomited at least 5 times over the course of the night).
Could this have been a placebo effect, because it had worked in the past and I wanted it to work so desperately? Possibly, but I was generally miserable for a period for a period of 10 hours, and the Coke settled my stomach very quickly. Coke is not an anti-diarrheal, but 10 hours into the illness there was nothing left.
Placebos and Nocebos are very complicated entities and a huge review in Neuron will tell you why. It’s very much worth reading – Neuron vol 84 pp. 623 – 637 ’14 — “Placebo Effects: From the Neurobiological Paradigm to Translational Implications”. The article contains references to studies showing that placebo is as effective as morphine on the third day post-op. In med school I’d heard stories to the effect that in Korea and WWII when they ran out of morphine on the battlefield, saline worked just as well. So probably these aren’t myths. It didn’t happen in Vietnam when I was in the service, as the country is long and thin, and no wounded soldier was more than 20 minutes away by chopper from a fully equipped field hospital (once they got him).
The ingredients in Coke are and were a closely held secret, but most think in the 1880s and 1890s, when it was sold as a medication, that Coke contained cocaine, hence the name. Back then, no one knew the potential of cocaine for addiction. Halstead the great Baltimore surgeon, got into it because cocaine is also a local anesthetic. Freud actually used cocaine to treat morphine addiction. Neither was malevolent, just ignorant.