The light blue sedan veered off a major road in the heart of the capital and slammed through a gate onto the grounds of Erawan Shrine, the site of a bombing in August 2015 that left 20 dead and scores injured.
"It was an accident," Lumpini police commander Pornchai Chalodet told AFP of the car crash.
"A lady had epilepsy while driving and couldn't control the car which went into Erawan Shrine. Four people were injured," he said.
The shrine, a popular stop for East Asian tourists, was thronged with worshippers at the time of the accident, according to an AFP reporter at the scene.
"We were praying and then suddenly we heard a big noise and we saw a car coming inside. We ran like crazy. It was very scary. At I first thought it was a car bomb but everyone was very calm around us," Kristy, a 21-year-old tourist from Vietnam, told AFP.
Police said they could not confirm the nationalities of those injured.
Two Uighur men from western China are on trial for the 2015 bombing that stunned the country.
They have both denied involvement in the attack.
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