There are two main approaches in science: empirical and experimental. Empirical research is based on practice, observation and analysis. Webster's Universal Dictionary of the English language (1937) defines the word empirical as "pertaining to experiments or experience." This type of research is very slow, but it has rather stable results. As an example, Chinese doctors have been documenting their experiences for thousands of years. Their successful and not so successful clinical cases (including experimental research) have been compiled in book form at the end of their careers. The basic principles, methods and techniques that are currently used in Chinese medicine were developed and established as clinical standards at least 2000 to 2500 years ago. These clinical standards are still very valuable, effective and useful today.
Experimental research is based on the scientific method and rooted in ancient Greek philosophy. This type of research leads to relatively quick results and conclusions. However, these results need to be confirmed by empirical science to become reliable because the research outcomes are not thoroughly tested in practice. For this reason, we have hundreds of recalls of pharmaceutical drugs that were approved as “safe and effective” by scientific studies and the FDA. However, we still have to proudly acknowledge that experimental research has resulted in the development of life-saving pharmaceuticals, tests and medical procedures.
Now let us give you a few links to studies that you may find interesting: Acupuncture helps headaches/migraines Acupuncture helps low back pain Acupuncture helps dementia including Alzheimer's disease