Antibiotics
You already know how crucial antibiotics are to the study of medicine. They are necessary in a variety of medical treatments, from minor injuries to complicated surgeries, therefore it would be bad if we suddenly ran out of them.
That's exactly what has been taking place for the previous few years, as you can infer from the list's overall tone. In addition to supply issues affecting the production of all medicines, we are now finding a number of novels, potent disease strains that are resistant to well-known antibiotics.
It might not seem like a big concern, but consider what would happen if you couldn't quickly treat a cold (or any medicine). The shortage of basic, daily medications we used to take for granted is made even more concerning by the fact that these strains are emerging quicker than we can develop and replace current antibiotics.
It is fueled by a number of things, such as widespread improper disposal of medical waste and overuse of antibiotics. Nevertheless, the major contributing cause is the absence of regulation and industrial safety requirements in some of the top producers of antibiotics, such China and India, where the issue is far more severe than in other nations.