Alshammar has now a medal of every colour in the event after winning silver at Fukuoka in 2001 and bronze at Montreal two years ago.
She clocked 25.91 seconds to down Australia’s defending champion Danni Miatke (26.05) and Inge Dekker of the Netherlands (26.11).
“It’s excellent. I feel terrific,” she said, revealing her secret was “dedication and focus.”
“I figured I wanted to go under 26 (seconds) again, but I tightened up at bit at the end as you tend to do in finals.”
The Swede equalled Dutch swimmer Inge de Bruijn’s record total of four medals in all 50m events at the FINA world championships.