The doctrine of res ipsa loquitur means
The doctrine of res ipsa loquitur  
It means “the thing or fact speaks for itself”.
In a case of professional negligence of a physician, the patient need not prove negligence.
It is applied when the following conditions are fulfilled :

That is the absence of negligence the injury would not have occurred ordinarily.
That the doctor had exclusive control over the injury-producing instrument or treatment.
That the patient was not guilty of contributory negligence.
Common knowledge
Medical maloccurance
Fact speaks for itself
Oral evidence