The 21-year-old Olympian fell as she got out of the water and was immediately surrounded by medical staff.
Slovakian swimmer Tamara Potocká has collapsed poolside after competing at the Paris 2024 Olympics.
Potocká, 21, fell on Friday morning just after a qualifying heat of the women's 200m individual medley and was given first aid and then carried off on a stretcher.
She was seen wearing an oxygen mask as she was taken away for medical attention. Medical personnel at the pool said she was conscious.
She collapsed as she got out of the water and almost immediately was surrounded by a half-dozen medical attendants who put her on a stretcher after about a minute and carried her off the pool deck.
It was not clear if she received CPR.
Israeli swimmer Lea Polonsky, who swam two heats after Potocká, said swimmers know their sport has inherent risks.
"Of course that's something in the back of your mind, but we do every day push ourselves to the limit," she added. "You always know something like that can happen. It's not something you think about during the race, but it's always there."
This is Potocká's first Olympics. She resides in the Slovakian capital of Bratislava.
She finished seventh in her heat in a time of 2 minutes, 14.20 seconds, leaving her eliminated from the semi-final round.