In some cases, the xenobiotic already has a functional group that can be conjugated and the xenobiotic can be biotransformed by a Phase II reaction without going through a Phase I reaction. A good example is phenol that can be directly conjugated into a metabolite that can then be excreted. The biotransformation of benzene requires both Phase I and Phase II reactions. As illustrated below, benzene is biotransformed initially to phenol by a Phase I reaction (oxidation). Phenol has the functional hydroxyl group that is then conjugated by a Phase II reaction (sulphation) to phenyl sulfate.