The kalam is a unique drawing also called "dhulee chithram" or powder drawing. The artist uses the floor as his canvas. Kalamezhuthu pattu is performed as part of the rituals to worship and propitiate gods like Kaali, Ayyappan or Vettakkorumakan.

This ritualistic art is a common feature of temples as well as noble households. The kalams or drawings are erased at the end of the ritual to the accompaniment of musical instruments like ilathalam, veekan chenda, kuzhal, kombu and chenda.

The coloured powders used for the kalam are prepared from natural products only. The pigments are extracted from plants - rice flour (white), charcoal powder (black), turmeric powder (yellow), powdered green leaves (green), and a mixture of turmeric powder and lime (red). It often takes more than two hours to finish a kalam drawing with appealing perfection.

The figures drawn usually have an expression of anger, and other emotions. Kalamezhuthu artists are generally members of communities like the Kurups, Theyyampadi Nambiars, Theeyadi Nambiars and Theeyadi Unnis. The kalams drawn by these people differ in certain characteristics.

Decorations like a canopy of palm fronds, garlands of red hibiscus flowers and thulasi or Ocimum leaves are hung above the kalam.

The Kalamezhuthu is a forty-day ritualistic festival beginning with the first of Vrischikam (Scorpio) in most Bhagavathy temples in Kerala.