The human being has a fragile life, and is attacked by different diseases throughout his life, neglecting or ignoring some of them because it is considered minimal, can be fatal, but many do not want to attend a health center, so they seek your symptoms on the Internet and finding pages with false information, that is the problem that we will address in this investigation. The objective of the research is to implement an expert system, creating a web page that provides real information when a user enters their symptoms. This was achieved based on the logic of rules developed in Prolog, so when a user fills out the created questionnaire, the expert system will follow. the rules to conclude with the desired diagnosis; all these steps were carried out using the buchanan methodology. The result was an improvement in the accessibility of truthful information through the Internet, facilitating the management of appointments of users if they have a serious illness, or the treatment in case of a minor illness. The beneficiaries of the research were the population that required the use of the automated query application.