I've been in Madrid for a week now, most of which has been spent thoroughly knocked off my feet by a combination of jet lag and the chest cold I seem to have picked up on the plane. I was expecting it to be a huge challenge to buy cold medicine here just because not only do the brand names of drugs differ, but even the generic names are not always the same. (For example, what we call acetaminophen, most of the rest of the world calls paracetamol.) However, as someone with multiple serious drug allergies, I do a fair amount of research and label-reading even in the US before I buy any kind of new medication; and this wasn't really any different than my normal practice.
This is coming to a point, I promise.
In the course of finding out that the cough suppressant guaifenesin is, in Spanish, just called guaifenesina, I also learned that in its natural form, it is the resin of the guayacá tree, which is native to Santo Domingo. The resin was first brought to Europe by the Spanish conquerers (although they initially hoped it would be a promising remedy for syphilis...).
So, I've not really done anything particularly Madrid-y yet, but at least I am taking culturally and historically appropriate cold medicine.