The incident occurred on Tuesday afternoon when the hiker and a female companion, accompanied by a dog, walked through a field near the Lac de Lovenex, Valais cantonal police said.
For a reason not yet explained, a herd of cows moved toward the couple, knocking over and injuring one of the hikers in the head, police said.
A Rega rescue team arrived on the scene by helicopter and treated her on the spot before flying her to Lausanne’s university hospital (CHUV).
Her condition is not believed to be life threatening, police said.
Authorities have launched an investigation into the incident.
Hikers in the Swiss Alps often encounter cows, which spend summers wandering Alpine meadows, many of them traversed by hiking paths.
While attacks are rare, they are not unknown.
The tourist website MySwissAlps.com recommends that people walking in the Alps should pass cows quietly and avoid getting too close to them.
“Cows, in particular when accompanied with calves, may act aggressively when disturbed,” the site advises.