Brainwashing

"My purpose, is to teach you."

- Til'vak

Brainwashing is a method used by one power to coerce, influence, or "teach" their subjects/victims into pledging his or her allegiance to them. The Goa'uld and Wraith often commit to brainwashing. However, Bra'tac is able to sense whether or not someone was brainwashed just by looking into his or her eyes.

Milky Way
One of the first notable brainwashing techniques first encountered by the Stargate Program was in 1997, when the Goa'uld queen Hathor used her pink breath to influence the Stargate Command personnel into falling into her whim. The effects wore off after she gated to Chulak.

In 1998, Apophis brainwashed Teal'c's son, Rya'c. He was primarily brainwashed with the purpose to lure SG-1 to rescue him and send him to Earth. Apophis coerced Rya'c into releasing a highly dangerous bio weapon implanted in his teeth to spread across the planet and kill all 6 billion Tau'ri. Fortunately, they caught Rya'c on his mission just in time, and his mind became free after Teal'c shot him with a Zat'nik'tel, neutralising the hold Apophis had on him.

The Goa'uld Seth, who hid on Earth for millenia, used nish'ta, a substance stronger than Hathor's breath to brainwash humans into joining his group, the Cult of Setesh. In 1999, SG-1 were temporarilly brainwashed by the nish'ta, but the brainwashing was broken through a similar method Teal'c used on Rya'c, by introducing an electric shock. They then broke all members of the cult by shooting them once with Zats.

In 2001, Teal'c was killed on Vorash, and transported to Apophis' mothership, where Apophis proceeded to revive, and brainwash him into becoming Apophis's First Prime again. After SG-1 eventually captured Teal'c, they attempted to break the brainwashing, which failed. Bra'tac resorted to confiscating Junior, so Teal'c would undergo the Rite of M'al Sharran. Fortunately, that method freed his mind, and pledged his allegiance to the Tau'ri once again.

In 2006, Ba'al captured several members of the Free Jaffa Nation and brainwashed them into joining him. One of the victims were Teal'c, who was able to break the brainwashing himself. After he killed one of the Ba'al clones, Teal'c told Cameron Mitchell that to resist the influence of others, knowledge of oneself is most important.

Pegasus
In Pegasus, the Wraith commit to brainwashing through different methods; they often feed on their victims and restore their life force until they were coerced via the Wraith enzyme in the system. Some of the notable victims include Satedans Ara, Hemi, Morika, Rakai, Tyre, and Ronon Dex. Hemi and Morika were killed due to the physical stresses of the process, while Tyre and Dex broke their brainwashing by going into withdrawal from the enzyme.