Gaano ka effective ang acupuncture? Kahit ba serious illness kaya nyang gamutin?

From what I know, acupuncture helps our system and body parts function well. It stimulates certain body points that can help us have a better sleep, relieve pain, or even improve digestion and emotional being. I am just not certain how effective it is for serious illnesses. It's still better to consult an expert in acupuncture