A heroic food delivery rider took a detour - to deliver a sick two-year-old boy to hospital.

The youngster, named Plawan Manathat, was in a car with his family when he began vomiting uncontrollably in Bangkok, Thailand, on Sunday (September 1) afternoon.

He suffered a seizure caused by a brain problem and passed out in his mother's arms leaving the family in panic as the car could not move in the heavy traffic.

But the motorcycle rider, Watchara Krasian, has been hailed a hero after letting the boy and his mother ride pillion then speeding through gridlocked traffic to deliver the youngster to hospital, potentially saving his life.

Grateful mother Ploypatchara Manathat said: ''I am very thankful to the motorcycle rider. My son might not be alive today if he hadn't helped.

''When my son passed out I was worried he could die without getting to hospital. I was so scared before of the traffic. It could have taken much longer.''

In a video taken by his mother, the young boy says: "Hi this is Plawan, I am getting better thanks to my hero."

Dashcam footage shows how the anxious mother Ploypatchara Manathat is heard crying and telling her husband that the boy was becoming worse.

She says: ''Please do something. He's getting worse and I'm afraid he will not make it.''

The couple were trying to treat the boy as much as they could when the father spotted a motorcycle trying to pass through the traffic.

The quick thinking father decided to stop the car and asked the motorcyclist a favour to quickly take Plawanto the closest hospital.

Food delivery rider Watchara immediately told the mother and son to hop on his bike. He then rushed them to hospital.

Fortunately, the boy arrived at the emergency ward just in time. The boy was diagnosed with a malfunction in the left side of his left brain which caused his body to have a seizure. He has been prescribed a course of treatment for two years.

Motorcycle rider Watchara, who works for ride hailing app Grab, said: "I spotted the car kept changing the lane so I tried to out run him, but again I was stopped by him.

"Then he lowered the mirror and told me to take his son to the hospital. The boy's mother also begged me so I told her to get on the back with her son.

"I did not care that the food I was supposed to deliver. I could see the mother was desperate as the boy stayed still as if he was dying.

"After dropping them at the fly over, I went on and delivered the messy pizza and explained the customer and the company about the incident."