|Boa constrictors kill by squeezing their prey to cut off its blood supply|
The terrified woman explained that the 5ft 5in (1.6m) snake had wrapped itself around her and bitten her nose.
She said she had "rescued" the snake and another boa on Wednesday.
An ambulance was swiftly dispatched to the woman, who was found lying in her driveway in the town of Sheffield Lake with the snake around her neck.
"It was wrapped around her neck and biting her nose and wouldn't let go," fire chief Tim Card said, according to the local Chronicle-Telegram.
"They had to cut its head off with a knife to get it to let go of her face."
The 45-year-old explained her plight to the 911 operator, pleading, "There's blood everywhere!"
"I've never heard of this before," the dispatcher exclaimed, before urging the woman not to move.
Boa constrictors kill their prey by gripping it so tightly that blood and oxygen can't reach the victim's vital organs.
The woman, who said she had 11 snakes, was taken to hospital for treatment after the incident on Thursday. Her injuries were not said to be life-threatening.
Mr Card said the emergency services had disposed of the dead snake in a bin near Sheffield Lake City Hall.
A local reporter who visited the scene that afternoon found an empty glass cage on the pavement, and a small pool of blood on the driveway.