A Canberra woman holidaying in Brisbane had a nasty surprise this week when a carpet python bit her on the bottom while she sat on the toilet.

A few days on from the bizarre ordeal, Helen Richards said she was able to look back on it and laugh, but she also wanted to warn people to "look before you leak".

Snake catcher Jasmine Zeleny pulls a carpet python out of a toilet in Brisbane after the snake bit Canberra woman Helen Richards. Credit:Helen Richards

Mrs Richards thought she was alone at her sister-in-law's house in Brisbane's west on Tuesday when she decided to do some ironing.

While she waited for the iron to heat up, she ducked into the toilet and didn't turn the light on before sitting down and feeling a mysterious "sharp tap" on her backside.