Want a Vacation Souvenir? Buy Toothpaste.

Six weeks after my first trip to Italy, the fresh mozzarella I brought home is long gone, and so is the hard salami and pistachio-flavored chocolate. To squeeze a bit more from my Mediterranean experience, I can rely a little while longer on the tube of Elmex-brand toothpaste I used to brush away all that food. For as long as it lasts, each day starts and ends with an ingredient called “Fluoruro Amminico,” which I assume has to do with fluoride but haven’t bothered to translate. The lingering sense of wonder it evokes is something I would rather not name.

Elmex is, strictly speaking, a Swiss brand, but its flavor, color and packaging will always for me be tied to the week I spent in Naples: the smell of the dewy summer air, the taste of plump local anchovies, the sight of Mount Vesuvius from the Riviera di Chiaia. I bought the toothpaste on the morning of my arrival, and spent scarcely a minute choosing Elmex over another brand. My habit of treating toothpaste as a souvenir is about celebrating rather than elevating the trivial — I’m not chasing quality, authenticity or meaning, those most overrepresented pursuits among world travelers. So I pick whatever seems fun, interesting or tame, depending on my mood. It’s a low-stakes exercise with just one rule: My selection must comply with the 100-milliliter limit for packing in my carry-on.

The effect of this habit is Proustian but its origin is not. About a decade ago, I chose to ignore some advice I was given before moving to Japan for a study-abroad program. Japanese toothpaste, I was told, might not be to my liking, so I should pack a few tubes of my favorite brand to take with me to Tokyo. Shunning even the most inconsequential new experience seemed to me a bad way of approaching a new life in a new country. I was 32 and had learned to wring all that I could from my days as a working stiff. Why shouldn’t I do the same as a slightly-too-old university student in Japan? I stretched my student loans and scholarship money so I could quench my thirst for novelty by drinking from the well of everyday experience — which, in Tokyo, runs deep with small consumer delights.

Among these delights, buying toothpaste I would never find in an American drugstore proved to be a reliable way of enlivening an otherwise unremarkable daily activity — one that we often treat as routine but that I try to embrace as a ritual for chasing the fog of sleep from my waking hours. Each new and unfamiliar flavor…