Background:Primary dysmenorrhea may lead to severe anxiety and pain relief during menstruation may reduce the anxiety levels. This study was aimed to determine the effect of acupressure at third liver and placebo points on the anxiety level in patients with primary dysmenorrhea.Materials and Methods:This clinical trial was conducted in parallel in the control and treatment groups for three menstrual periods at the dormitory of Kashan University of Medical Sciences between March and June 2012. Students with pain score equal to or greater than 4 were selected and divided into groups based on severity of pain using a randomized block design with the allocation ratio of 1:1. Acupressure was applied in two acupoints including third Liver point (Liv3) and placebo points. Spielberg (STAI) anxiety questionnaire was completed before and after intervention. Randomization, subjects, and data analyzer were blinded to the analysis. Chi-square tests, t-test, Mann-Whitney, paired sample t-test, and univariate analysis of variance were used for statistical analysis. P values <0.05 were considered statistically significant.Results:Mean [standard deviation (SD)] values of apparent anxiety levels before and after intervention for liv3 were 45.100 (9.769) and 38.100 (10.608), respectively. For the control group, they were 41.200 (9.795) and 38.900(10.140), respectively. Difference was significant only in the intervention group (P < 0.001). Hidden anxiety did not show a significant change before and after intervention. There was no difference between groups in apparent or hidden anxiety after intervention.Conclusions:Pressure on liv3 point reduces anxiety. As there are no previous studies on this topic, further studies with more samples are recommended.