Smudging is a ritual or ceremony to remove purify or bless people or places. Smoke attaches itself to the negative energy and removes it to another space. "Cleansing" is the word traditionally used, but you can think of it as a shift in energy from any bits of negativity to a more positive, peaceful state. Smudging can be used to cleanse an object, a place, or your spirit, mind or body. Native Americans often use smudging in association with other ceremonies using only the sacred herbs of that tribe deemed for purification or blessing. The herbs of one tribe may by deemed "taboo" or "sacred" in another. Hence "smudging" is referred to this practice of First Nation or Native American tradition.
In many traditions, smudging involves a four directions ceremony or prayer. It, thus, sends specific kinds of smoke or prayer into the four different directions. Of course, different tribes have different smudging prayers, but the smoke is typically directed or programmed to do a specific action or a specific direction, aiding in divination. However, in general smudging is used to maintain balance and shield against negative energy. As has been noted above, it is often used as a cleansing agent.
In many traditions, smudging involves a four directions ceremony or prayer. It, thus, sends specific kinds of smoke or prayer into the four different directions. Of course, different tribes have different smudging prayers, but the smoke is typically directed or programmed to do a specific action or a specific direction, aiding in divination. However, in general smudging is used to maintain balance and shield against negative energy. As has been noted above, it is often used as a cleansing agent.