Legend has it that one day when the temple priest was removing the vesture from the idol of Goddess Parvati; he noticed the presence of blood stains on the dress. The priest informed the local ruler about the unusual occurrence and the queen who examined the dress realized that it was stain of menstrual blood and it was confirmed by the women in the family of the priest.
The shrine of Goddess Parvati was immediately close and invoked Goddess Parvati into a processional idol. The priest also arranged for some women to sleep in the temple to keep company of the Goddess. The ceremony is continued even today when the senior-most woman in the family of the temple priest confirms menstrual blood on the dress
On the fourth day after menstrual bleeding occurrence, the processional idol is taken into a nearby river for Arattu â" the ritual bath â" on an elephant. The arattu is known as Thripootharattu.
The idol of Goddess Parvati is then taken back to the temple. Lord Shiva waits for Goddess Parvati in front of the temple on another elephant and they together encircle the temple three times. A grand Kalabhabhishekam concludes the ritual. The dress with the menstrual blood is displayed in the temple for devotees to offer prayers.
The dress with the menstrual blood is in great demand and it is said to bring good fortune. Advanced booking is necessary to get the attire and the wait is usually 10 to 15 years.
Many people in the past have ridiculed the idea of the divine menstrual bleeding and some officials during the British rule tried to stop the ceremony. But they themselves had to restore the ceremony primarily due to mysterious happenings to the women in their family related to menstruation cycle. Atheists and skeptics are still questioning the ritual but devotees in large number arrive at the temple for the ceremony.
The latest Thripootharattu ceremony is on 15th August 2007.