I recently heard of a man who had back surgery. After the operation was over, the hospital kept him on a cart for four hours because it didn’t have any rooms available for him. All the others were occupied by people who had the flu.

Influenza is everywhere. You can’t drop a Kleenex without having it land on someone who has it. We are standing on the corner of Hemagglutinin and Neuraminidase, and it will only get worse from here.

What can you do when a friend or loved one comes down with the flu? That hyper-crud that has been going around? Or even a really bad cold? Other than stay away, of course, because you really don’t want to catch that stuff.

The best way to show a fallen loved one that you care is, of course, with food. The way to an invalid’s heart is through his stomach, and if you can bring a meal that he or she doesn’t have to make, that just makes life easier for those who are suffering.

The classic get-well-soon meal is, of course, chicken soup. It’s often called Jewish penicillin, which is funny, but there is also this: It may actually be slightly, a little bit, true.

A New York Times story back in 2007 explored the rationale behind the anti-cold, anti-flu properties of chicken soup, and concluded that several factors may play into its medicinal effectiveness.

For one, soup is a liquid, and it is essential for cold- and flu-sufferers to remain hydrated (when they say “drink plenty of liquids,” they aren’t kidding). Also, the chicken and vegetables in it provide nutrients that can help battle the virus.

But there is reason to believe — though the research is not definitive — that there is more to it than that. One researcher, using his Lithuanian grandmother’s recipe for chicken soup, collected evidence showing that the soup limited the movement of the type of white blood cells that fight infection, thus helping to combat an upper-respiratory infection.

The same effect was seen with other, commercially available types of chicken soup. But you can bet they didn’t taste as good.

Another study showed that hot fluids help clear stuffed-up noses, and that chicken soup did a better job of this than hot water.

One reader wrote to say that she recently succumbed to the same viral muck that has left offices half-empty, and that she greatly appreciated the bean soup — the “elixir of life,” she called it — that was sent by a friend. Bean soup may very well have the same medicinal properties as chicken soup, but without the good PR campaign.

Now that she feels better, the reader sent along some tips to share with others who want to give food to people who are sick:

— It is best if what you send can be frozen, in case the patient is not feeling up to eating it that day. It is also best, she hints, if it comes in a container that is disposable.

— Send food, especially soup, that you know the patient will enjoy. Don’t send something with “weird stuff” in it that you have never seen him eat (The reader must be a picky eater, and your sick friends may well be, too. I, on the other hand, am all in favor of weird stuff).

— If you bring over takeout soup, make it from a great restaurant that you have enjoyed with the patient. The reader goes on to say that some soups, such as hot and sour soup, do not travel well. I disagree, especially about hot and sour soup. That said, people with a cold would probably prefer a thinner broth than you find in many hot and sour soups.

— Even soup in a can is good for an ill friend — especially, says the reader, when it is served “with nice cookies.”

— You could do worse than send along some bread or cake. Everybody likes bread. And cake.

— Don’t forget how welcome a gift card from a local restaurant would be for when your friend is feeling better but is not yet up to cooking for herself.

Great ideas, all. If you know someone who is under a significant amount of weather, you know what to do.