Pepper spray attack clears a Yaletown pub in Vancouver on Friday night, sending 20 people running into the street with seared eyes and throats.

First responders were called to the Tavern pub on Hamilton St. around midnight after a scuffle turned spicy.

Pub patrons said there seemed to be some sort of altercation leading up to the attack.

Miarco Iannaccone was inside the pub eating chicken wings at the time.

"I heard a sound, like 'shshshsh,' sound of a spray and something getting broken, and then everyone started running out."

"Everything inside there started to burn, like the face, the air, everything," said Iannaccone. "I came outside and everyone was feeling pain in the eyes, and in the throat, because they were breathing the stuff."

Officials said about 20 people needed medical treatment outside after the attack. People who witnessed the attack said many more experienced minor effects.

A man struggles to overcome the effects of pepper spray, after an attack in Yaletown Friday night. (Rafferty Baker/CBC)

"Then the police came and the ambulance and they gave us some soap for the eyes, and water for cleaning our face and people were getting sick," said Iannaccone.

Police said the suspect fled the restaurant and took off in a vehicle. No description of the vehicle has been provided.

Firefighters used a powerful fan to ventilate the pub.

Iannaccone said he was hoping the staff would re-open the pub so he could go back inside to finish his chicken wings, which he had abandoned on the table when he fled.

"Unfortunately, they're still there," he said.