Four people suffered bumps and bruises but no-one was gored during the running of the bulls in Pamplona on Tuesday, the Spanish Red Cross said.
Spokesman Jose Aldaba said the injuries on the fourth day of the San Fermin festival included leg and head injuries in the relatively clean and fast run through the old quarter of the city.
The six fighting bulls weighing as much 1,360lb (620kg) stayed together in a pack for much of the dash, which is preferable because an isolated bull is more likely to get disoriented and charge at people.
Four more runs remain at Spain's best known summer festival.
Two Britons and an American were gored in Monday's run but none was seriously hurt.
Tuesday is the third anniversary of the last death at San Fermin, that of a young Spaniard.