They are non-venomous. Cape house snakes are usually dark brown on top, but the colour varies greatly from almost black through brown to olive green. The stripes that stretch from the rostral scale through the eye to the back of the head are very strong, thick, and bold. This species may have a lateral stripe running down the flanks.
By Erikpaterson - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=4490147
Slang
This species is known to frequent human habitations, feeding on the rodents that gather there. Nocturnal by nature, this species is known to eat entire nests of mice in one sitting.