Our friends at Wireless Flash called and asked an interesting question.  "If vampires are affected by the smell of garlic, are ghosts affected by the odor, and repelled?"
The answer is no.  Spirits are not affected by odors.  It is energy that affects them, thought, and, vibrations.  Though they sometimes manifest odors in their appearances, these odors are to benefit the living to let them know they are in the vicinity.  They do not effect the Spirit in any way.
If someone puts a deceased Loved One's favorite flowers around a room to attract them, it is not the smell of the flowers that attracts the Spirit, but the thoughts of the person desiring their presence that brings them forth.  The flowers act as a focal point to concentrate the living person's energies, and create a passage through which their Loved One can approach.
No, odors do not effect Spirits, but they have a profound effect on the living.
Wireless Flash's question brings up another subject.  Why are vampires effected by garlic, and, are there such things as vampires?
I wish I could answer no, that there are no vampires, but this would not be completely true.  The legendary creatures that can turn into bats and fly do not exist.  This is just the stuff of legend.  But there are vampires.  They suffer from a disease that is called by most, Vampex.  Most human beings are genetically immune to the disease, but when a small percentage of them come in contact with it, they begin to have an uncontrollable craving for human blood, as the disease causes their bodies to be drained of an enzyme that is only found in human blood.  And the only way they have of staying alive, is by draining and consuming the blood of others.
The disease also makes them photo tropic; extremely sensitive to ultraviolet light.  Their exposed flesh would burn quickly if exposed to direct sunlight.  They can venture out during the day, but they must be completely covered, so they prefer the night.
Vampex does not make its victims immortal, but it does prolong their life cycle by two or three times so those that suffer from it DO have an increased life span.
Garlic DOES repel vampires because of their altered chemistry, they are violently allergic to it.  It is toxic to them.  It causes their blood to coagulate, and if they should ingest it, can cause death in minutes; quite agonizing death.
Those that live in regions where garlic is heavily used, often keep their victims captive for several days, feeding them food without garlic, until the substance so poisonous to them is drained from their victims' bodies, and they can feed without fear.
Vampex outbreaks are rare but common enough that they have become a part of human legend.
There is another danger vampires face.  Certain individuals carry an antibody to Vampex.  Should they ingest the blood of one of these individuals the virus in them would be destroyed, and without it they would no longer be able to absorb the enzyme to keep them alive, and within a few days would starve to death.
Unfortunately vampires can usually sense these individuals, but once and a while, driven by hunger they make a deadly mistake.
Usually every legend has some basis in truth.  We wish vampires didn't but sometimes evolution creates some very unpleasant things; some very, VERY unpleasant things!