Three people have been gored during the first bull run at the annual San Fermín festival in Pamplona.
Officials say those with gore injuries are two US citizens, aged 23 and 46, and a Spaniard.
Two others were taken to hospital with head injuries and a total of 48 others were treated by the Red Cross.
Six bulls are released daily, along with steers, before later facing professional matadors in public bull fights.
Those taking part, most dressed in white with red scarves, packed into the 850m course – which leads downhill to the town’s bull ring.
Further runs will take place every morning through the northern Spanish city’s narrow streets until next Sunday.