A reaction inhibitor is a substance that prevents or decreases the rate of a chemical reaction. When an inhibitor reduces the rate of an uncatalysed reaction, it can be called a "negative catalyst". The word "inhibitor" can also be used to designate a substance that reduces the effectiveness of a catalyst (either a non-biological catalyst or an enzyme). Non-biological catalyist inhibitors are often referred to as "catalyst poisons".

See also

• Enzyme inhibition

Catalysts