Emergency responders in Mobile said the 41-year-old man stuck a finger in the mouth of what was believed to be the head of a cotton mouth and the snake's fangs broke his skin, WALA-TV, Mobile, reported Wednesday.
The man initially refused medical treatment, but paramedics were called back to the scene when the man began showing the effects of venom poisoning. He was taken to USA Medical Center for treatment.
A friend of the man said he spotted the snake swimming in a nearby creek.
"I saw it swimming down along the creek and everything. And I ran down and hit it with the machete and killed it and brought it up. He picked the head up and stuck himself right in the finger with it," the friend said.
"He put his finger in there and all of a sudden the nerves, I guess, and it bit down on his finger."