On occasion, I've found myself with a nasty headache in a restaurant; and when I've asked the front desk whether they had any aspirin (or whatever else, but I'll just say aspirin for now) I could have, they've always said no.
Now my sense is that, like most employers, they do have some aspirin for their staff, likely in those little individually wrapped packets. It's also probably in their interest to help out with it: If I've got a bad headache, I'm going to have a less pleasant dinner, and while I probably won't consciously resent them for not helping, I'll be slightly less likely to come back soon (since often one comes back to a restaurant because of memories of recent pleasant dining experiences there). And of course giving me some of the aspirin would cost very little money and time. So why not help out, especially given that they're in a service industry where the presumption (I'd think) is that they should try to help the customer with simple requests that could make him happy?
One possible theory, which I recall having heard a couple of times from restaurants, is that they don't want to give out aspirin for fear of product liability should anything bad happen to me. But I don't really see the real liability risk: There's nothing negligent in their giving me something that I could buy over the counter at a gas station — it's not like they're giving me medical advice. Given that they're not negligent, the only extra risk is strict product liability, but that only arises in the extraordinarily rare circumstance the aspirin was somehow defective; and even in that rare case, it's likely that the payment would come from the manufacturer, not the distributor, with the distributor being on the hook only if the manufacturer is insolvent.
So is it that the restaurant just doesn't want the hassle of helping me? That, contrary to my assumption, they don't have aspirin around for the staff? That they fear liability without much foundation, because there's some industry myth about it afoot (or because they just haven't looked into the legal question, and err on the side of caution)? That, contrary to my sense of tort law, they may in fact be legally on the hook if I react badly to the aspirin? Or something else?
UPDATE: A recurrent thread in many responses is that the restaurants are afraid even of a tiny risk of litigation, and are reasonable to be afraid of it. I wouldn't generally fault them for it; I'm sympathetic with such concerns. Still, if the risk of litigation is really tiny -- some commenters suggest that it's not, but I'm still not persuaded -- wouldn't they at some point conclude that keeping a customer happy is worth the tiny risk of even a huge hassle and cost? (My guess is that much of the cost would be insured, by the way, though I'm not sure.) After all, despite the supposedly "paralyzing" risks of litigation (I quote one of the commentators here), business do lots of things that have some litigation risk.
Some other commenters dealt with this, by suggesting that businesses will run litigation risks in what they see as the core area in which they must, but will shun even tiny risks outside that area. This isn't necessarily so -- for instance, though I hear that many businesses have tamed down their Christmas parties, many do still have them, even though any such activity involves some extra risk (harassment litigation, lawsuits from people hit by employees who drive home drunk, and so on), and even though it's far from obvious that such parties are really necessary to build morale -- but I suspect it's part of the explanation. Still, I think one needs some such explanation and not just a theory that businesses will always avoid any risk of liability, however unlikely.