Toxication is the process of metabolism in which the metabolite of a compound is more toxic than the parent drug or chemical. A parent drug or chemical that was previously non-toxic may be called a protoxin.Toxication may involve:While toxication is generally undesirable, in certain cases it is required for the in vivo conversion of a prodrug or chemical to a metabolite with desired pharmacological or toxicological activity. Codeine is an example of a prodrug, which is metabolized in the body to the opiate known as morphine.