Abstract: A disposable fever indicator is provided to determine whether or not a predetermined body temperature has been reached. The indicator comprises a vessel containing therein a movable member and means for exerting a force to move the member from a first position to a second position. The indicator further includes meltable bonding means disposed within the vessel and adapted to overcome the force exerted by the aforementioned means and keep the member in the first position until the predetermined temperature is reached at which time the bonding means melts and allows the member to move to the second position under the action of the force exerting means. The indicator is armed only prior to usage. Prior to arming the device, even if the predetermined temperature is reached or exceeded, the movable member will remain in the first position.