This temple is located near Thiruvisai Nallur about two km from Thiruvidaimarudur and 7 km from Kumbakonam. The main deity is Lord Sri Shiva in Linga form known as Sri Karateshwarar.
According to the temple legend Lord Indra worshipped this Lingam with 1008 lotuses everyday. Varuna was given the task of creating these lotuses in the temple tank. One day lndra was short of one flower at the time of puja. When questioned, Varuna was confident that he had created 1008 flowers. This shortage continued everyday. Ultimately one day Indra found that one flower was moving from the water and was taken by a crab and placed on the Siva Lingam. The crab was golden in colour. Indra thought that this crab was an asura who wanted to spoil his puja. He raised his hand to hit this crab when it made a hole on the top of the Siva Lingarn and entered into it. There upon Lord Sri Shiva appeared and blessed the crab. The crab was actually a Yaksha in the previous birth and had attained this form due to the curse of Sage Sri Durvasa, since the Yaksha mimicked Durvasa's gait as a crab. Even now there is a hole in the Siva Lingam and the place is known as Thiru Nandu Devan Kudi. It is believed that persons born with the star sign Aahilyam in Kataka Rasi can overcome their difficulties' by worshipping this Sri Shiva.
Since Kataka Rasi is-the house of planet Chandra, there is a idol of yoga Chandra in this temple.
This place was originally an Oushadha Vanam (forest of medicinal herbs). In olden days there was a ayurvedic dispensary here. This Lord Sri Shiva was originally called Sri Oushadeeshwarar; he was supposed to have cured an infectious disease of the Chola King, assuming the form of old man. Lord Sri Shiva is also known as Sri Arumarundha Devar.
There are two shrines for ambal namely Sri Arumarundu Nayaki and Sri Apoorva Nayaki situated side by side. The idol of Sri Arumarundu Nayaki was once stolen and later on recovered. Hence the original idol came to be known as Sri Apoorva Nayaki. There is a moat surrounding this temple known as Sri Thirumaruvam Poighai.
People born under Ashlesha Nakshatram (Ahilyam) will be blessed if they perform Puja in this temple on Ashtami, Tuesdays and Saturdays except the Janma Nakshatram day. Lighting nallennai Vilakku is considered to be auspicious.
There is an idol for Sri Dhanwantari. Generally Sri Danwanthar idols are found only in Vaishnava temples but there are three Sri Shiva temples that house these idols; in each of these temples, the main Lord Sri Shiva is the Lord of medicine. The other two Sri Shiva temples are Sri Vaideeshwaran Koil near Sirkazhi and Marudeeshwarar Koil in Tiruvanmiyur in Chennai.