The Plak tow was a Vulcan word which meant "blood fever" and refered to the final stages of Pon farr. Common factors during this stage during the Vulcan mating ritual is highly combative behavior as well as a high fever. Vulcans are noted to be almost unable to speak or think clearly while they are subject to the Plak tow. (TOS episode: "Amok Time") The fever can only be broken by the Koon-ut-kal-if-fee: either through the successful completion of the marriage ceremony or through combat. (VOY episode: "Blood Fever")