Rationale - Patients treated with homeopathy may respond to infrequently used or even ‘new’ medicines. But does the introduction of an unlimited number of (new) medicines improve homeopathy? Do new medicines solve old problems?Methods - 1. Consensus meetings to evaluate best cases. 2. Patient outcome study in 10 Dutch practices.Results - Good cases are scarce for many medicines, random variance is an important source of uncertainty. 50 Medicines are responsible for 72% of all successful prescriptions. There is no difference in effectiveness of frequently and less frequently used medicines. Confirmation bias is found for a few well-known symptom-medicine combinations.Conclusion - ‘New’ and infrequently medicines are as effective as ‘old’ frequently used medicines. Improving the use of frequently used medicines is more effective in improving results than seldom used medicines. Large numbers are required and old mistakes should be avoided developing new medicines. A research agenda for improving the use of homeopathic medicines is imperative.