Part C of the guideline is preceded by Part B General Pharmacology IJCPT. 2008; 46: 600 - 617. Included in Part C are practical guidelines for improving the therapy of some age-specific diseases and problems commonly encountered in general practice. The article in this issue is dedicated to the therapy of Dementia and M. Parkinson. Further guidelines for the other age specific diseases and problems named above will be published in the following issues of IJCPT. An important feature of these guidelines are the inclusion of Levels of Evidence and of the Strength of Recommendations for the therapy which are shown when reliable studies are available. (For both see levels of evidence at the end of this article.).