special subjects
Traditional Chinese Medicine
Evidence for Traditional Chinese Medicine
Obtaining high-quality evidence is difficult, mainly because the active ingredients in TCM herbs are not purified, are often unidentified, and may be numerous. Thus, determining the dose is difficult or impossible, and the dose may vary from one source of herbs to another. Information about bioavailability, pharmacokinetics, and pharmacodynamics is usually unavailable. Also, active ingredients may interact with each other in complex and variable ways. Chinese herbal medicine traditionally uses formulas containing mixtures of herbs to treat various disorders. Traditional formulas can be studied as a whole, or each herb in the formula can be studied separately. One herb, used by itself, may not be as effective and may have adverse effects. Nevertheless, current conventional research favors study of single herbs to better control for variables. Another problem is the large number of herbal mixtures that could be studied. Systematic reviews and meta-analyses of studies (most done in China) have shown evidence for efficacy of TCM for the following: Symptoms of Tourette syndrome ( References ) Chronic kidney disease, when combined with Western medicine ( References ) Depression following stroke, when combined with Western medicine ( References ) Possibly depression during menopause and perimenopause, when combined with acupuncture ( References ) Possibly certain outcomes in COVID-19 (eg, resolution of chest imaging findings and cough), when combined with Western medicine ( References ) Possibly acute gouty arthritis ( References ) Possibly quality of life and symptom management in small cell lung cancer ( References ) Many of these reviews had significant limitations, suggesting the need for confirmation with further prospective studies. Studies of TCM herbs and herbal mixtures for irritable bowel syndrome have had mixed results, and reviews of these studies conclude that more rigorous studies are required. 