Up-to-date overviews of research in herbal medicine can be found at:

• Memorial Sloan Kettering Cancer Center website
  scientific name, common name, brand name, clinical summary, purported uses, constituents, mechanism of action, adverse reactions, herb-drug interactions, herb lab interactions, literature summary and critique, references. 
• European Scientific Cooperative on Phytotherapy - ESCOP
  publications on the quality, safety and efficacy of herbal medicines in Europe. 
• European Herbal & Traditional Medicine Practitioners Association - EHTPA
  document 'Scoping the Evidence for Herbal Medicines' and others.