Variations of HRV and skin conductance reveal the influence of CV4 and Rib Raising techniques on autonomic balance: A randomized controlled clinical trial Introduction: The aim of the present study was to evaluate whether Fourth Ventricle Compression Technique (CV4) and Rib Raising (RR) osteopathic techniques influence Autonomic Nervous System (ANS) activity, as measured by Heart Rate Variability (HRV) and Skin Conductance (SC). Method: A randomized-controlled clinical trial has been performed from June 2010 to January 2011. 32 healthy adults (33.9 ± 14 years, and 72% female) were selected. Subjects were randomized in three groups: CV4 group, RR group and Placebo group. Each subject of each group underwent respective technique only once. HRV and SC were continuously recorded during the session. All data analysis was performed using SPSS statistical software (version 21.0) and the significance level was considered at p 0.05. Results: RR technique intra-group subject analysis showed a significant decrease in LF/HF ratio (F ¼ 25.18; p < 0.001), a statistically significant decrease of LF (F ¼ 27.09; p < 0.001), and increase of HF, both at the end of treatment (F ¼ 27.09; p < 0.001). CV4 technique intra-group subject analysis showed a significant reduction of the LF/HF ratio (F ¼ 81.15; p < 0.001), a significant decrease in LF (F ¼ 38.29; p < 0.001) and a significant increase of HF, at the end of treatment (F ¼ 38.28; p < 0.001). Between-group analysis showed only a significant difference in LF/HF ratio between CV4 and PL groups (F ¼ 3.44; p ¼ 0.042). Discussion: Our results suggest that the application of CV4 and RR techniques favors a shift in the autonomic balance towards a parasympathetic predominant state. Thus, their use within OMT protocol, as holistic approach, might improve the outcome of the treatment of clinical neuro-vegetative conditions.