The 67 years old actor was undergoing treatment in Thiruvananthapuram.
He acted in 46 movies and about 100 serials. He also penned many short stories.
Vallathol entered showbiz through soap operas and plays.
Some of his notable performances were in movies like 'Mathilukal', 'Naalu Pennungal', 'Vidheyan', and 'Samantharangal'.
( With inputs from ANI )