Two Britons and an American were gored in the running of the bulls through the streets of Pamplona in northern Spain, the regional government said.
Thousands of daredevil runners charged ahead of six fighting bulls on the third day of the annual San Fermin festival.
The trio were gored by an animal which broke free from the pack just before entering the city's bullring, a Navarra government statement said.
The bull, which weighed 1,202lb, charged the runners as they huddled on the ground beside a wooden fence, trying to protect themselves from it. After several moments of tension, the animal was lured away by stick-wielding cowherds. None of the three was seriously injured.
The morning runs are the highlight of the annual San Fermin festival, which became world famous with the publication of Ernest Hemingway's 1926 novel The Sun Also Rises.
The regional government said one Briton, aged 20, was gored in the right leg while the other, aged 29, was gored in the left leg. The American, aged 39, was gored in the right calf muscle.The three, identified only by their initials, were taken to the city's Navarra Hospital.
The Spanish Red Cross's preliminary report had put the number of people gored at two.
Four other people were treated for cuts and bruises sustained in the adrenaline-fuelled dash along the 928-yard (849m) course today. The run lasted just over three minutes.
The following footage was recorded at the San Fermin festival on Sunday:
The bulls from the Cebado Gago breeding ranch were herded from a holding pen in the city centre to the bullring, where they are normally killed by matadors in afternoon bullfights.
Fifteen people have been killed by bulls in the runs since record began to be kept in 1924.
The runs take place daily until July 14 and are broadcast on state television.