Wei Kang inherits a pharmaceutical company on the verge of bankruptcy.
The company poured a fortune into developing a new drug, only for it to fail. Rivals are squeezing them out and the bank is demanding repayment. His parents both died in a car accident, and now he has suddenly developed cancer.
Luckily, he awakens a pharmaceutical black-tech System that can extract certain side effects from drugs and use them to create new medicines.
As it happens, the failed drug the company just developed contains a side effect that can effectively inhibit cancer cells, with a success rate of 0.01%.
So he takes the discarded formula and starts extracting side effects.
The blood pressure medication does nothing to lower blood pressure, but has the side effect of relieving pain. Extract that side effect, and it becomes the best painkiller on the market.
The fever medicine has no effect at all. It doesn't lower your temperature, but instead speeds up your metabolism. Extract that side effect, and it becomes a beloved weight-loss drug.
The eye drops are too irritating, and even cause hair follicles to grow more densely. Extract that side effect, and they become the most popular hair-growth treatment.
Extract, extract, extract!!!
Wei Kang not only cures his own terminal illness completely, but also becomes the greatest god of medicine in human history.