The Goa'uld healing device is a hand device used by the Goa'uld to instantly heal a person.
The healing device of the Goa'uld is a mechanism consisting of a large red crystal emitter which can be slid on one's hand. Like other Goa'uld hand devices, the healing device can only be used by people who have Naquadah in their blood such as Goa'uld, Tok'ra, and former hosts. Its operation appears to be similar to the Goa'uld ribbon device (Kara kesh), as it seems to require strong desire or emotion from the user to activate. It is also possible to make the device light up but not work, as Nirrti did when she bluffed trying to heal Cronus with the device. The device is capable of healing Staff weapon wounds, several diseases and even near fatal injuries. It is however not as powerful as a Sarcophagus and can't revive the dead.
Although it is unknown how the Goa'uld invented the healing device, it is quite possible that it was created using data from the Ancient healing device, similar to the sarcophagus.
SG-1 first made contact with such a device when they visited the planet Cimmeria, where it was used by the former Goa'uld host Kendra to heal injures of the Cimmerians. When Heru'ur took over the planet one year later, Kendra was killed and her Goa'uld devices came into the possession of Stargate Command. (SG1: "Thor's Hammer", "Thor's Chariot"). This device was used several months later by Samantha Carter to heal the injuries of Cronus after he was injured by Nirrti in order to prevent a war with the Goa'uld. Although ultimately successful, Carter expressed concerns that she hadn't been a host long enough to use the device effectively. (SG1: "Fair Game")
When curing Cassandra Fraiser of the retrovirus she was afflicted with, Nirrti used a healing device combined with another instrument from her lab to try to cure Cassandra. The first attempt failed with Nirrti stating that they had waited too long, but Dr. Janet Fraiser insisted she try again and after a second longer try, Nirrti succeeded in curing Cassandra. (SG1: "Rite of Passage")
When Daniel Jackson was mortally wounded due to Naquadria radiation, both Sam and Jacob Carter tried to heal his injuries with a healing device. When Sam attempted to use the device on Daniel, it worsened his condition. Jacob had better luck, perhaps due to the presence of a current symbiote. Although the device may have been able to heal him, Daniel told Jack to make them stop so he could ascend. (SG1: "Meridian")
Vala Mal Doran had apparently been host to the Goa'uld Qetesh long enough that she was able to use the healing device as effectively as a blended individuals, and used a healing device to help the people of P8X-412 after they were infected with a deadly plague by a Prior. Although she was able to heal many at first, the device lost its effect later when the Prior adapted the plague to be resistant to such technology. A year later, Vala, now a permanent member of the SGC and SG-1 used another such device to heal members of SG-25 who were attacked by a mutated beast on P9J-333. (SG1: "The Powers That Be", "Uninvited")