AbstractBackground.Herpes zoster infection particularly involving the sacral dermatomes has been associated with bladder and bowel dysfunction, most commonly urinary retention.Case Reports.We report two patients who developed acute urinary retention, one of whom also had constipation, within days of herpes zoster skin lesions of the S2‐S4 dermatomes.Conclusions.Herpes zoster is a reversible cause of neuro‐genic bladder and bowel dysfunction and should be considered in a patient that presents with acute urinary retention and/or constipation. Sensory abnormalities and flaccid detrusor paralysis are most likely involved in the pathogene