Almost only thing acupuncture can do is pain relief

There is good scientific evidence for acupuncture's effectiveness in relieving:

post-operative pain
nausea during pregnancy
nausea and vomiting resulting from chemotherapy
nausea and vomiting following surgery
dental pain
headache
back pain
pain from osteoarthritis of the knee

Acupuncture is also used in many other common illnesses such as depression and asthma but the evidence is not clear and more studies are needed to prove the effect of acupuncture.