Approximate reasoning is one of the most effective fuzzy systems. The compositional rule of inference founded on the logical law Modus Ponens is furnished with a true conclusion, provided that the premises of the rule are true as well. There exist different approaches to an implication, being the crucial part of the rule, but we are especially fond of the results brought by the early implication proposed by Zadeh, which is modified in our practical model concerning a medical application. The approximate reasoning system, grounded on the extended version of Modus Ponens law, will be employed here to predict a chance of positive effects of the operation on a patient who suffers from stomach cancer. The patient’s CRP (C-reactive proteins) symptom level, pathologically heightened, indicates the presence of a disease. When the CRP-value does not exceed a critical border it can be realistic to try surgery to recover the patient from his/her illness due to Do-Kyong Kim. We wish to evaluate the verbal prognosis of the surgery by involving particularly designed fuzzy sets in the algorithm of approximate reasoning.