Published: May 23, 2026, 01:31 IST | Updated: May 23, 2026, 01:31 IST
Hay fever in Japan, known locally as kafunshō, has become one of the country’s most widespread seasonal health problems, affecting more than 40% of the population. The allergy is mainly triggered by huge waves of pollen released by Japanese cedar (sugi) and cypress (hinoki) trees planted extensively after World War II.
Cedar pollen season typically begins in mid-February and peaks in March, while cypress pollen follows from mid-March through May. The annual allergy wave causes severe discomfort for millions, impacting daily life, productivity and public health across Japan.