Vitalum Vitalis is used to balance the scales of life and death. This can be used by either draining one's own life force to restore a dying person's health, or to cure injuries and diseases, or even resurrect a dead person. Unlike Resurgence, Vitalum Vitalis uses the witch's own life force to bring the dead back to life, which may cause the user to pass out, though the life force eventually restores itself and apparently the Supreme doesn't have these consequences when using this. Vitalum Vitalis can also be used to drain the life force of other living things too.
Fiona Goode used this when she sucked the life out of David Zhong through a kiss after he couldn't make her a youth drug. She regained her youth, and looked younger, but this only lasted for a few minutes. She used it the other way after Queenie was killed by the Minotaur to bring her back before her soul went to the afterlife. She used this again when roaming around the hospital after Cordelia's acid attack where she stumbled into a crying mother whose baby had died. After forcing the mother to tell the baby she would always love it, she brought the baby back to life, much to the mother's delight. Zoe Benson also manifested this ability when she resurrected a homeless man whom Kyle had killed in a fit of rage after the man had insulted them.
After Zoe was killed during the Trial of Transmutation, Queenie and Madison, took turns trying to resurrect her using vitalum vitalis. Queenie went first and was unable to, disqualifying her from the test. Madison was able to but didn't, much to everyone's shock. She instead used her ability to kill and then resurrect a fly. After being scolded by Myrtle and Cordelia, she told them off, telling them Zoe 'lost fair and square'. This was when Myrtle then encouraged Cordelia to participate in the Seven Wonders, as she had 'royal blood' in her. After completing all the other tests, Cordelia used Vitalum Vitalis to resurrect Zoe, bringing her back to life. She then collapsed due to the strain, allowing her to ascend to the Supremacy.
The young candidate for Supreme during the Seven Wonders skit was able to give another witch some of her life force which resulted in one of her hands to age. 
- Vitalum Vitalis is quite similar to the Last Kiss also known as the kiss of life, a magic rite or power practiced by the red priests of the Lord of Light in the fantasy-novel series A Song of Ice and Fire. When a person died, priests fill their mouth with fire and breath flame into the deceased, reviving them back to life.