ELI5: Explain Like I'm 5

Active ingredient

An active ingredient is like the superhero in your medicine. Just like how Superman saves the day in his movies, the active ingredient saves your body from the bad guys (aka germs or sickness).

When you take medicine, there are usually a lot of different ingredients in it - kind of like how Superman has a lot of different powers. But, just like how flying is Superman's most important power, the active ingredient is the most important ingredient in your medicine because it fights the sickness or disease you're trying to get rid of.

The active ingredient is like the boss of your medicine that tells all the other ingredients what to do. So, even though there are other ingredients in the medicine, it's the active ingredient that does all the hard work of making you feel better.