The internet is an excellent aid in making diagnoses. One can retrieve diagnostic information from a reliable source such as a continuously updated textbook or search specifically for a diagnosis in bibliographic databases such as PubMed. Entry of a patient summary in a general search engine or a large language model such as ChatGPT can suggest differential-diagnoses to the expert user,but one must be conscious of the limitations of current large language models. There seems little room left for the traditional differential-diagnosis generators. Ideally, large language models will be combined with transparent algorithms with which medical data can be retrieved, to create a new generation of diagnostic decision support systems.