Yuzuyu

In Japan, there is a traditional custom to take a yuzuyu (yuzu-bath) on the winter solstice.
Yuzuyu refers to the bath in which citrons(yuzu) are put and set afloat.
Yuzuyu has an effect to alleviate the feeling of cold, neurosis, backache and so on.
It is said in Japan that taking yuzu-yu (a yuzu citron bath) and eating Toji-gayu (winter solstice rice gruel), which is azuki-gayu (rice gruel with red beans), and pumpkins on the day prevent catching cold.