Many different studies have already been done to explore the effects of placebos. However, in the following thesis the placebo effect, when using the hand-dynamometer, (under consid-eration of different caffeine intake) has been researched for the first time. The aim of this paper is to detect, if the simulated caffeine content increases the measurable strength. Through verbal suggestions and the intake of decaffeinated coffee the test persons were influenced. Furthermore, the study participants were told a cover story.41 volunteers at the age of 23 (+- 2,3 years) participated in the study. The participants were all male sport students.The measurement took place on four testing days, within a month. On the first test day the baseline measurement was taken. Two weeks later, at the same time and place, the second test, which has been done identically, was conducted. During this trial the study participants drank 40ml-decaffeinated coffee 15 minutes before the test. The subjects were told that they drank coffee with little caffeine content. During the third test, the volunteers thought that they drank very strong coffee with high caffeine content. The last trial was done with the baseline measurement to control and prove that during the testing period there was no training effect and improvement in strength.The following research questions will be discussed in the diploma thesis:-How does the simulated information about the caffeine dose influence the isometric strength?-To what extent does regular caffeine consumption influence the placebo effect?Due to the consumption of coffee (constant, rarely, never) significant differences were meas-ured between the baseline test and test 2 and 3.Between test 1 and 4 there is no significant difference. Thus a learning effect can be exclud-ed.