Primary dismenore is a menstrual pain which comes without pathological sign at real sexual organ. The frequency of dismenore at Kediri 5 High School was still high, according to the survey result that many students still didn't know how to decrease dismenore. This research used pre experiment method with the one group pretest-posttest design. The research population was all of the XI class student at Kediri High School 5 whom got dismenore at April 2016. The sample was 16 respondent which taken by accidental sampling. Primary data which is got from dismenore pain measurement at teenager which is done before giving the dark chocolate (pre test) and after giving the dark chocolate (post test) used observation sheet with numeric scale value (Numeric Rating Scale-NRS). Data analysis used wilcoxon test. The result of wilcoxon test analysis showed ρ value < α (0.001<0.05). It showed that giving dark chocolate has an effect on primary dismenore pain on teenager. By this result, teenager can use dark chocolate as non pharmacologic alternative therapy to heal primary dismenore pain, because dark chocolate has less side effect, so student can do activity comfortable when they are in menstrual period.