A lot of medical research is done in the laboratory or in lab animals, not in people — at least, not at first. Lab studies help scientists figure out whether a drug looks promising, how it works, and whether there might be side effects. But what happens in a laboratory does not necessarily work the same in people. These studies are often a beginning — but they're usually not the end of the story.
When watching or reading a news report about a new drug or treatment, see if it tells you whether the findings involved animals or people. It might not — so you'll have to do some sleuthing on your own to get the information.