Ovarian hyperstimulation syndrome due to exogenous gonadotropin administration is life-threatening in its most severe form. Profound fluid shifts may occur, with concomitant cardiovascular changes. We present a case of severe ovarian hyperstimulation syndrome managed with chlorpheniramine maleate (previously shown to be effective in animal models) and invasive hemodynamic monitoring. Mannitol and albumin infusions were also used to maintain urine output and intravascular volume.