Californian White Sage is also known as Bee Sage - as its flowers are extremely attractive to bees, hence it's Latin name, Apiana - or Sacred Sage, because of its use in religious ceremonies by various Native American tribes.
White Sage is used for emotional, psychic, and spiritual purification. The ritual of smudging can be defined as "spiritual house cleaning." In theory, the smoke attaches itself to negative energy and as the smoke clears it takes the negative energy with it, releasing it into another space where it will be regenerated into positive energy. Never leave lit smudge unattended and care should be taken when extinguishing.