After the formation of PMK, and under the leadership of Ramadoss, PMK was able to obtain a significant share of power both in the regional government in Tamil Nadu and the central government, primarily due to coalition pressures. Ramadoss's son, Anbumani Ramadoss, was the Health Minister in the Government of India.
Ramadoss, being the leader of a caste centred party, is often alleged to have instigated caste violence in Tamil Nadu against Dalits and Viduthalai Chiruthaigal Katchi (VCK), a Dalit based party. In the northern districts of Tamil Nadu with a Vanniyar majority, there are frequent clashes between Dalits and Vanniyars. During 1999 general elections, there was intense violence in the region with casualties in both sides. Thirumavalavan, the leader of VCK accused Ramadoss of instigating violence among the Vanniyars that resulted in the attack of Dalits. While Ramadoss alleges that Thiruma encourages his party men to have sham inter-caste love marriage, Thiruma accuses Ramadoss of showing caste superiority and instigating violence against Dalits. Both Thiruma and Ramadoss reconciled and worked together during the period of 2004 to 2009, when they were part of the same electoral alliance. During 2004, after efforts from N. Sethuraman from MMK, Thirumavalavan and Ramadoss, the leader of PMK joined hands through a Tamil protection movement named Tamil Paathukappu Iyakkam. After 2009, when PMK split out of the DMK combine, the mutual confrontation started again.
During December 2012, Ramadoss formed an all community safeguard forum comprising 51 intermediate castes. He said he would not have any further alliance with Thiruma and his party. He alleged that the Dalits take undue advantage over other communities using the SC/ST Prevention of Atrocities Act and the Act should be abolished.
 During April 2013, after the party conference of PMK in Mahabalipuram, there were widespread attacks on the Dalits in Dharmapuri district that resulted in two Dalits being killed. Both PMK and VCK accused each other for the mishap, but Ramadoss was arrested after the orders from the state government for the hate speech and damages to the state property during the violence. Thiruma accused Ramadoss that his loss in the electoral base after the 2009 general elections and 2011 assembly elections has resulted in his going back to instigating caste violence.
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- "Thirumavalavan allegation baseless: Ramadoss". The Hindu (Chennai). 18 November 2012. Retrieved 30 November 2013.
- Wyatt 2009, pp. 122-123
- "Brahmins support new Forum, says Ramadoss". The Indian Express (Coimbatore). 22 December 2012. Retrieved 30 November 2013.
- K.S., Durairasu (10 December 2012). "Ramadoss's caste cauldron reheats anti-Dalit call". India Today (Chennai). Retrieved 30 November 2013.
- "CM blames Ramadoss for caste clash, warns of action". The Times of India (Chennai). 30 April 2013. Retrieved 30 November 2013.
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- B., Jothi Ramalingam (31 May 2013). "A dangerous strategy". Frontline. Retrieved 30 November 2013.