SEOUL (Reuters) - South Korea's baseball players have been banned from putting frozen cabbage leaves under their caps to beat the summer heat.

The Korea Baseball Organization (KBO) took action after Doosan Bears pitcher Park Myung-hwan's cap fell off during a game last weekend, revealing his secret cooling agent.

After an emergency meeting, KBO officials ruled that cabbage leaves are a distraction and cannot be considered part of the baseball uniform.

"Park has been using frozen cabbage to cool down since last summer, but we didn't know until now," KBO chief of referees Heo Koo-youn told Reuters Wednesday.

"We had to act because imagine if it happened in the World Series. If something drops out of the pitcher's cap, it could put the batter off. Does the umpire call strike or ball?"

Park, who twice dropped leaves on the mound during last Sunday's game with the Hanhwa Eagles, said he was disappointed with the ruling but would not appeal.

"I'm sensitive to the heat and my wife recommended I put frozen cabbage leaves under my cap to cool my head," he said.

"I will respect the KBO's decision. Even without the cabbage, my pitching won't be affected."