Nocebo is the antipode of placebo and refers to adverse events a person manifests after receiving placebo. Recent findings: In randomized trials for migraine prevention meta-analyses revealed that eight out of 20 patients treated with placebo experienced any adverse event. More importantly, one out of 20 patients treated with placebo withdrew treatment because of adverse events. The adverse events in placebo groups mirrored the adverse events expected of the active medication studied, confirming that pretrial suggestions induce the adverse events in placebo-treated patients. Nocebo was higher in preventive treatments than in symptomatic ones.