A 26-year-old man, a drug addict, has allegedly killed his mother during an argument while she was cooking outside their home in this district, police said on Friday.
The incident took place in a village near Pallikkathodu on Thursday night.
Police identified the victim as Sindhu, 46, who sold lottery tickets to support her family.
Her son, Aravind, a former JCB driver, had allegedly been struggling with drug addiction and was undergoing treatment.
According to the police, only the mother and son were at home at the time.
They began arguing while Sindhu was preparing food. Aravind then attacked her with a sharp weapon, killing her on the spot.
Neighbours, hearing the noise, rushed over and found Aravind sitting beside his mother's body. Police arrested him at the scene.
Sindhu's younger son is a student living in Alappuzha.
Her body was taken to a hospital for post-mortem examination.