In the Sweet Dew incident, Emperor Wenzong (pictured) of the Tang dynasty conspired to kill the powerful eunuchs of the Tang court, but the plot was foiled.

The Sweet Dew incident or Ganlu incident was a failed coup on December 14, 835 by Emperor Wenzong of the Chinese Tang dynasty to seize power from the eunuchs. The emperor planned to kill the eunuchs with the aid of the chancellor Li Xun and the general Zheng Zhu. The eunuchs learned of the plot and solidified their control with a counter-coup; Li, Zheng, many of their followers and other officials were killed.

Emperor Wenzong of Tang (809–840), personal name Li Ang, né Li Han (李涵), was an emperor of the Tang dynasty of China. He reigned from 827 to 840. Emperor Wenzong was the second son of Emperor Muzong and younger brother of Emperor Jingzong. A rare occurrence in Chinese history, Emperor Wenzong, along with his elder brother Emperor Jingzong and younger brother Emperor Wuzong, reigned in succession.

The Tang dynasty, or the Tang Empire, was an imperial dynasty of China that ruled from 618 to 907, with an interregnum between 690 and 705. It was preceded by the Sui dynasty and followed by the Five Dynasties and Ten Kingdoms period. Historians generally regard the Tang as a high point in Chinese civilisation, and a golden age of cosmopolitan culture. Tang territory, acquired through the military campaigns of its early rulers, rivalled that of the Han dynasty.

A eunuch is a male who has been castrated. Throughout history, castration often served a specific social function. The earliest records for intentional castration to produce eunuchs are from the Sumerian city of Lagash in the 2nd millennium BC. Over the millennia since, they have performed a wide variety of functions in many different cultures: courtiers or equivalent domestics, for espionage or clandestine operations, castrato singers, concubines or sexual partners, religious specialists, soldiers, royal guards, government officials, and guardians of women or harem servants.