Introduction - The Swiss randomised controlled trial of homeopathy for attention deficit hyperactivity disorder (ADHD) was a rigorous test of homeopathy. In each of its three phases it delivered evidence for a specific effect of homeopathic treatment, but it also unmasked weaknesses of the method. Misleading reports of sensations and mind symptoms by parents were frequent, while modalities and polar symptoms usually proved to be reliable information for repertorisation. The problem of cases with a paucity of symptoms was resolved by reintroduction of (pathognomonic) perception symptoms into the repertorisation. Additionally polarity analysis, a further development of Boenninghausen's concept of contraindications, was tested and introduced. It allows a precise differential diagnosis of possible homeopathic medicines. Increasing the rate of optimal prescriptions by 20%, polarity analysis turned out to be the most efficient modification to case analysis. This paper describes the transfer of the new insights to the treatment of other diseases and as the evaluation of this process.Methods - Polarity analysis was tested and applied in acute diseases by completing patient histories with repertory specific checklists, mainly based on modalities and polar symptoms. The checklists encompassed eleven different complaints. Treatment results were compared with results reached by conventional homeopathic case analysis methods. The same procedure was applied in chronic diseases with repertory-specific questionnaires. Again, eleven different areas were covered. Treatment results for chronic diseases were also compared with a conventional case analysis approach.Results - Polarity analysis, checklists and questionnaires led to an increase in optimal prescriptions of 22% in acute diseases and 16% in chronic diseases. In addition, the average improvement rates in chronic disease were 9% higher than with conventional homeopathic procedures. The new method is demonstrated by a case example with a verified clinical cure, and its impacts on homeopathy are discussed.Conclusion - The use of polarity analysis as an integral part of case analysis and differential diagnosis of possible remedies together with an increased awareness for assessing the reliability of symptoms in repertorisation lead to a substantial improvement in the precision of homeopathic prescriptions.