The first line treatment of OCD is Cognitive Behaviour Therapy (CBT) which includes Exposure and Response Prevention (ERP) when the patient tests out their fears without responding by compulsive act (NICE Clinical Guideline 31). ERP treatment itself is often associated with significant subjective distress (Kellner et al 2012) with dropout rates up to 20% and only minimal improvement in another 20% of patients (Foa 2010). Various modalities of treatment reducing the subjective and physiological distress have been used in treatment of anxiety disorders and symptoms (Streeter et al 2012, Miu et al 2009, Gorman et al 2000) and similar approach could increase the rates of improvement and adherence to ERP treatment in OCD. Most of the attempts to reduce distress in anxiety focus on re-establishing the sympathovagal balance by enhancing the vagal or parasympathetic tone and it has been suggested that this can reduce the mobilization behaviours of fight or flight response and improve emotion regulation (Austin et al 2007). Disgust is an emotion implicated to have significant role on anxiety disorders such as OCD with contamination fears (Moretz and McKay 2008). It has been shown to have only limited response to exposure therapy (Olatunji et al 2009) and can be associated with increased avoidance and reduced compliance with exposures (Olatunji et al 2007) possibly contributing to poorer treatment outcome. Disgust can be associated with changes in sympathovagal balance (Ottaviani et al 2013) but the effect of manoeuvres affecting this balance has not been tested.