A placebo response refers to the improvement in a patient's clinical symptoms when administered with an inert substance, whereas a nocebo response is the worsening of clinical symptoms. The neuropeptide oxytocin is implicated in social trust, stress/anxiety, and learning processes that also contribute to placebo and nocebo responses. This leads to an intriguing hypothesis that pharmacological manipulation of oxytocin 1nay modulate placebo/nocebo. It has been proposed that oxytocin may enhance social trust, a key element of the patient-doctor relationship, which may further boost placebo effects. Oxytocin has also been shown to be involved in reducing stress and anxiety, which might contribute significantly to the magnitude of nocebo.