The post showed Crenn in a car on the way to her first chemotherapy appointment on Tuesday May 14.
In honor of that, she shared what she described as "a beautiful poem from a beautiful person."
Here is the transcript of the poem:
"Dear Chemo, Oh how I thank you. Thank you for your healing. Thank you for lighting up the dark spaces. Thank you thank you a million times thank you."
The post has received thousands of reactions including from many well-known chefs around the world.
Crenn revealed on social media on May 5 that she diagnosed with cancer.
She acknowledged that one in eight women have breast cancer, and shared a token of inspiration for them too.
"For all the women who have been on this journey before me and now with me, my heart is with you," she wrote.
Crenn says she is going to remain in her kitchen as much as possible while she fights the disease.
She has three restaurants in San Francisco including Atelier Crenn, which has earned three Michelin stars.
Crenn is the first female head chef to be awarded three Michelin stars.