Fuzzy set theory has used many auxiliary methods into the trials of solutions of some medical problems. One of the attempts was the evaluation of the optimal level of the drug action in the case when the clinical symptoms disappeared completely after the treatment. However, there can occur such a morbid process in which the symptoms prevail after the treatment. The medication improves too high or too low level of the quantitative symptom but it still indicates the presence of the illness. It is not so easy to choose the medicine, which acts best because it can happen that most of them influence the same symptoms, while they do not improve the others. A fuzzy decision making model tries to make easier to find such a drug which affects most of the symptoms in the highest degree. In the next attempt of solving the problem we propose the using of discrete membership functions in the model instead of the continuous ones. It should improve the thoroughness of the method and heighten the reliability of the accepted decision.