Hwang Soo-kwan, the doctor known for his trademark "smile therapy," died Sunday aged 67. The cause of death was blood poisoning.
One close aide to the doctor said he died peacefully with his family by his side.
Hwang had been admitted to Gangnam Severance Hospital in Seoul on Dec. 11 complaining of a high fever, according to his family.
The doctor became famous with his 1997 book "Sinbaram (Excitement) Therapy," describing how smiling keeps you healthy. The book became a bestseller and since then he was busy lecturing until recently about the secret to health.