In humans, disease is the cause of health problems in the human body that attacks a number of people. Humans often know that their bodies have health problems, but do not know exactly what diseases are attacking them and how to treat them, so that to find out and deal with diseases an expert who understands health problems (doctors, midwives, or nurses). Typhoid is a disease whose incidence is quite extensive and can attack anyone regardless of age and ethnicity. The current obstacle is the general public's ignorance of the disease they are experiencing due to the high costs that must be spent to find out the disease early without having to consult a doctor. So it is necessary to have a system that can make it easier for patients to diagnose the disease experienced early to prevent the disease to a higher level. The method that will be used in this research is the Bayes method which is a method to prove whether a fact is certain or uncertain in the form of a metric that is usually used in expert systems.