A 19-year-old woman has been gored on the second day of Pamplonas controversial Running of the Bulls festival.
Spanish authorities say she did not need hospital treatment after a horn tore into her back.
But two men and a woman were hospitalised with head injuries or severe bruises as thousands were chased down the streets by bulls.
One received a blow to the head and was taken to hospital still conscious and another is thought to have broken his left shoulder.
Another was kicked in the back while a fifth was treated for bruises.
It comes after five runners were sent to hospital after the festivals opening yesterday, including two Americans and a Spaniard who were gored by bulls.
A 46-year-old man from San Francisco needed surgery after being pierced in the neck in the citys bullring, at the end of the 850-meter course.
A 23-year-old man from Florence, Kentucky and a 40-year-old Spanish man were both gored in the thigh.
The nine-day fiesta in northern Spain draws about one million spectators every year.
Six bulls, surrounded by tame bullocks, are run every morning in the citys narrow streets before being slaughtered in afternoon bullfights.
Some Americans come to follow in the footsteps of Ernest Hemingway, who immortalised the Pamplona festival in his 1926 novel The Sun Also Rises.
Animal rights protesters have become a regular fixture at the festival.
On the eve of the party, dozens of semi-naked activists from around the world lay simulated speared bulls by lying on the cobbled streets of Pamplona.