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.
Dunno about cabbage leaves, but I've stuck a zip-lock sandwich bag partly filled with crushed ice underneath my hat, and it cooled for quite a long time. (Not recommended for bald men unless the ice bag is wrapped in a washcloth or sandwiched between two feed caps.)
Even better are the cool vests. I decided to buy one this year because of the excessive heat we had last summer. While they don't prevent sweating or being hot, they do prevent overheating. They contain about 4 lbs of phase change chemical which melts at 65 degrees. That makes the vest warm enough that the blood vessels don't constrict, and cool enough to keep the body core temperature down. They are expensive, but still a lot less expensive than the entire winter wardrobe I'd have to get if I moved north.