The alleged incident was caught on camera.
The mother was booked on one count of unlawful delivery of a controlled substance to a minor and one count of manufacture of marijuana.
Police say the video of a Centralia, Washington, mother shows her 22-month-old boy take a hit off her marijuana bong. On the video, the boy coughs and people can be heard laughing.
The boy's mother, 24-year-old Rachelle Braaten, was arrested for allegedly giving the child pot. The boy and his 5-year-old brother are now in state custody.
Police raided the mother's home after investigating the cellphone video of the boy sent to them anonymously.