Classical pharmacology is one of the approaches used for clinical trials on Ayurvedic drugs. In this approach, a folk medicines (e.g., Ayurveda) which has already been in use for many years and has anecdotal evidence of efficacy for the treatment of a disease (and is also presumed to be safe) is then tested for efficacy in a clinical trial. This method has been described as ’reverse pharmacology’ by Dr. Ashok Vaidya.