When my children were little, if they complained about aches and pains, I’d sometimes rub some moisturizer on them and tell them the “cream” would help. It often did. The placebo effect is surprisingly effective.

Moisturizer is cheap, it has almost no side effects, and it got the job done. It was a perfect solution.

Other treatments also have a placebo effect, and make people feel better. Many of these are dangerous, though, and we have to weigh the downsides against that benefit.

Lots of Americans have chest pain because of a lack of blood and oxygen reaching the heart. This is known as angina. For decades, one of the most common ways to treat this was to insert a mesh tube known as a stent into arteries supplying the heart. The stents held the vessels open and increased blood flow to the heart, theoretically fixing the problem.