Karuppan's famous work Jathikummi, which criticised the prevailing caste system, was written in 1904 during the period of his study at Kodungallur Kovilakam and it became popular among the poor. Jaathikkummi is a pioneering attempt in Malayalam literature questioning the caste system and untouchability. While Sree Narayana Guru, Kumaran Asan and Ayyankali worked for social changes in the Travancore State, the presentation of Jaathikkummi was the first step initiated in that direction in Cochin State by Karuppan, who was then a 19-year-old student.