Sugar Is Not Sweet (Thai: น้ำตาลไม่หวาน or Namtarn mai warn) is a 1965 Thai romantic comedy film written and directed by Rattana Pestonji.

Chaokun Charoenkesa, the owner of a shop that sells hair-loss treatments, wants to pay back his debt of kindness to a friend, whose formula is responsible for the Chaokun's prosperity.

So he arranges for his good-for-nothing son, Manas, to marry Sugar, the daughter of his dear friend.

Rattana Pestonji has a cameo appearance in this film as the doctor who treats Chaokun in his moment of death.

You can help Wikipedia by expanding it.This article about a romantic comedy film is a stub.