The woman had taken the child to the Siddha practitioner and as suggested by him had given the mixture of honey, medicated camphor and powdered pepper to stop diarrhoea.
However, as the girl's condition worsened, she was rushed to the Government Hospital at Palayamkottai here.
The doctor, who checked the baby, said the mixture had turned into a toxic, and gave her treatment. But she did not respond to the treatment and died.
Police registered a case and investigating the matter.