The 69-year-old lifestyle guru wrote on her blog Thursday that she needed stitches after startling her dog Francesca while leaning down to "whisper goodbye." The dog jumped up and rammed into Stewart.
She writes that she "felt a bit of whiplash as blood gushed" from her split lip Tuesday night.
She initially called police to ask for a ride to the hospital but realized her driver was waiting to drive her from her home in the suburbs to New York City for a "Today" show appearance.
Stewart landed in the Northern Westchester Hospital emergency room and received stitches in her upper lip.
She posted photos of the mishap on her blog.