It took the number of gorings to eight for the same amount of bull runs at the week-long event that draws around one million people a year.
A bull named Rabanero broke away from a pack of six as it was charging through Pamplona’s twisting streets on Sunday.
The animal caused havoc as it ploughed into crowds of runners.
Rabanero flipped one man over its horns and slammed him onto the cobblestone street, before clipping another two runners who were trapped against a wall.
Tomas Belzunegui, regional hospital spokesman, said the man who was tossed by the milk chocolate-coloured bull was gored in the leg.
Another was gored in the right arm and a third in the armpit.
He said all three were taken to hospital.
The Red Cross reported several other injuries from knocks received from the bulls and steers, or from runners tumbling out of the way.
The six Miura bulls, a fighting breed, were from a farm celebrating a record-extending 53rd showing at the festival.
They completed the 930-yard (850m) run to the bullring in two minutes and 42 seconds.
The previous seven bull runs of the 2019 festivals had led to five gorings – three of the injured were Spaniards and the two others were American.
Each year the animals are killed in the ring after the final run.
The San Fermin fiesta was made famous internationally by Ernest Hemingway in his 1926 novel The Sun Also Rises.
Most revellers stay up all night or rise early enough to watch from balconies or barricades as hundreds of runners dressed in the traditional white outfit with a red sash make their mad dash.
Animal rights protesters have also become a fixture at the festival in recent years.
On the eve of the festival, dozens of semi-naked activists staged a performance simulating speared bulls lying dead on Pamplona’s streets to draw attention to what they see as animal cruelty for the sake of entertainment.
Bullfights are protected under the Spanish Constitution as part of the country’s cultural heritage.