A bed siderail has a vertical siderail extension, a horizontal siderail extension, or both. A bed siderail has dual vertical siderail extensions. A bed has gap fillers pivotally mounted to the headboard and/or footboard, either in the manner of a hinge, or by means of a dual axis pivot, to fill gaps between the headboard/footboard and a siderail. A bed siderail has pivotally mounted gap fillers directed toward the headboard, footboard, or an adjacent siderail. A bed has slidably mounted gap fillers. A bed siderail has pivotally mounted gap fillers, to fill a gap between the siderail and a mattress, the gap fillers being either gravity- or cam-activated, or being integrally formed in the siderail support arms. A bed siderail is rotatable from a deployed to a stowed position, and is simultaneously stowed close-into or underneath the bed frame.