Out of interest, what can go wrong if you ingest some elderly Aleve? 
I'm still (occasionally) using some that expired a while ago on the basis that the worst that can happen is that it becomes ineffective! 
Yes, drugs can lose their potency (say the pill contains 80 mg active ingredient rather than 100 mg), but that would suggest that the active ingredient has degraded into something else. What it has degraded to may not necessarily be fully researched; and it could have potential genotoxic effects.
Also, people generally store medication in the bathroom - which can become a hot, humid atmosphere on a fairly regular basis. Most stability data generated for drug products is based on closed bottles, with the foil induction sealed liner still in-tact, and where applicable, the silica desiccant canister still in the bottle (desiccants keep the product itself from absorbing too much moisture). In your bathroom cupboard -- this is likely not the case. The first thing you do is pop the foil, chuck the desiccant in the bin, take what you want, and put it back in the cupboard for a few years.
Also, depending on the formulation- microbial growth is more likely to happen in liquid formulations than solid ones (for example "liqui-gel" capsules). if there are any preservatives present in the formulation, it may be possible that these also degrade and are no longer effective at warding off microbial growth. Throw in the hot, moist, dark environment and you've got a nice breeding ground!
Now - how likely is any of this? I'd say it depends on the product. I'm sure that many thousands of people have consumed expired medications in the past, and will continue to do so well into the future. For something like tylenol/aleve/advil, I imagine it's not that big a deal; however, I also don't work for McNeil/Bayer/Pfizer, so honestly without seeing the data, I can't exactly conclusively say that.
Personally, I prefer that the UK sells these sorts of things in smaller packaging - saves space in my cupboard, the individually wrapped "blister packaging" offers considerably more protection against the bathroom's humidity, and it ensures that I actually manage to use them up before they go off. But do I still sometimes find expired products lurking? Yes. Do I ingest them? Depends, but more than likely (so long as it's not >2 years gone). That's my own personal choice (or stupidity?), but I feel that I've made an informed decision, and have already weighed the risks over the benefits.
Wow that was longer than it should've been...
In respect of the original thread....I also bring back packs of Band-Aid brand plasters and Neosporin every time
I prefer Band-Aid brand plasters to the kind they sell here, but my OH prefers the kind here, so we normally have a pack of each. But Neosporin -- I don't think a decent alternative exists here!
