Most Americans take a lot of pills, some prescribed by their doctors and perhaps just as many that we buy over the counter. Those of us with type 2 diabetes probably even take more than most people.

Many pills are wonderful. Some may even be live-saving.

And others can cause big problems. Personally, I have tried five different statin drugs to help control my cholesterol, and every one of them gave me excruciating muscle pains. I also can’t take Bactrim, a widely prescribed antibacterial...