The 33-year-old Spaniard was in testing on Sunday ahead of the first Formula One race of the season next month, when his McLaren car left the track and hit a wall. He was "conscious and speaking," according to his team.
Fernando Alonso was taken to hospital by helicopter after crashing his McLaren on the final day of Formula One pre-season testing in Barcelona on Sunday.
The two-time world champion had managed just 20 laps when he hit the wall on the exit of turn three at a speed of up to 240 kilometers per hour (150mph).
"Fernando was driven to the circuit's medical centre where the circuit's doctors gave him first aid," McLaren said in a statement. "He was conscious and spoke with the doctors."
According to track officials, the Spaniard was transported to hospital "to continue with medical tests" after being treated at the circuit medical center.
"It seems that Alonso is ok. We hope that everything's alright and all ends with just a shock!!" tweeted the Circuit de Catalunya, which will host the fifth race of the 2015 season, on May 10.
Overnight stay in hospital
McLaren team boss Eric Boullier was later quoted as saying Alonso would be kept in hospital overnight as a precaution.
Alonso was airlifted to hospital after undergoing first aid in medical facilities at the Barcelona circuit.
The other Spanish driver on show on Sunday, Carlos Sainz Junior of the Italian Toro Rosso team, also crashed at the same part of the track but was able to walk away from a check-up unharmed.
Alonso, 33, won back-to-back world titles with Renault in 2005 and 2006 before spending one season at McLaren in 2007.
He rejoined McLaren this season after five years with Ferrari, who tweeted "All the best Fernando" after learning of his crash on Sunday.
McLaren has been plagued by technical problems this pre-season after switching to Honda engines ahead of the upcoming season. It was unsure whether the crash was a result of a driver error or a malfunction with the car.
The 2015 Formula One World Championship begins with the Australian Grand Prix in Melbourne on March 15.