A generic drug (or simply generic ) is a pharmaceutical drug that
contains the same chemical substance as a drug that was originally protected
by chemical patents. Generic drugs are allowed for sale after the patents on
the original drugs expire. Because the active chemical substance is the same,
the medical profile of generics is equivalent in performance compared to their
performance at the time when they were patented drugs. A generic drug has the
same active pharmaceutical ingredient (API) as the original, but it may differ
in some characteristics such as the manufacturing process, formulation,
excipients, color, taste, and packaging.