What subjects are mandatory in o level to become a doctor?

There isn't a universally fixed set of *mandatory* O Levels (or GCSEs, their equivalent in some countries) to become a doctor. The specific requirements vary considerably depending on the country and the university you plan to apply to.

However, almost all universities requiring O Levels/GCSEs for medical school entry will insist on strong passes in:

* Mathematics: Essential for understanding many medical concepts, particularly pharmacology and physiology.

* Biology/Double Award Science (including Biology): This is absolutely fundamental. A deep understanding of biological processes is the bedrock of medicine.

* Chemistry: Crucial for understanding the body's chemical processes, pharmacology, and medical treatments.

* English Language: Necessary for clear communication with patients and colleagues, as well as for academic writing.

While these four are almost universally expected, some universities may also require a pass in a further science subject (like Physics) or a language other than English. It's also vital to check the specific entry requirements of each university you're interested in applying to, as they will outline the exact subjects and grades needed. These requirements can vary significantly even within the same country.