The way real medicine is practiced and should be practiced (reduced detail): Someone comes up with a drug/surgical procedure/whatever that looks promising as a means for treating a condition. Cell culture and animal tests follow, overseen by ethical review boards and similar institutions. Records are kept of all results, positive or negative. If the results come out positive enough, human trials can begin, which are monitored even more carefully, starting out relatively small and, when ethically possible, controlled to compare the treatment versus placebo. The subjects must be followed up on to make sure they don't develop any long-term problems. Appropriate regulatory bodies must approve of the treatment before it is allowed on the open market. Records continue to be kept afterward in case long-term problems show up so that the treatment can be pulled or restricted if necessary.
The typical altie way: Skip all that and "experiment" directly on whoever's desperate enough to pay. Record only positive outcomes. Never follow up. Make excuses and never admit responsibility for negative outcomes. Scream bloody murder if someone suggests regulation or testing. Scream especially loud if someone suggests rigorous pre-market testing.