The American Psychiatric Association, defines a phobia as an irrational and excessive fear of an object or situation.
Bacillophobia: Fear of microbes.
Bacteriophobia: Fear of bacteria.
Ballistophobia: Fear of missles or bullets.
Barophobia: Fear of gravity.
Basophobia or Basiphobia: Inability to stand. Fear of walking or falling.
Bathophobia: Fear of depth.
Batonophobia: Fear of plants.
Batophobia: Fear of heights or being close to high buildings.
Batrachophobia: Fear of amphibians, such as frogs, newts, salamanders, etc.
Belonephobia: Fear of pins and needles. (Aichmophobia)
Bibliophobia: Fear of books.
Blennophobia: Fear of slime.
Bogyphobia: Fear of bogies or the bogeyman.
Bolshephobia: Fear of Bolsheviks.
Bromidrosiphobia or Bromidrophobia: Fear of body smells.
Brontophobia: Fear of thunder and lightning.
Bufonophobia: Fear of toads.
If left untreated phobias can progress to other mental disorders, like depression and substance abuse.