Nitrogen mustard is a chemotherapeutic agent that has a well-documented safety and efficacy profile in the treatment of cutaneous T-cell lymphoma. Development of nitrogen mustard formulations and treatment regimens has been studied extensively over the last 40 years. In the last 5 years, a new gel formulation has been developed that is associated with a decrease in delayed hypersensitivity reactions. The authors in this review found that while the gel formulation may result in a decrease of allergic contact dermatitis, this advantage has been replaced by a higher number of irritant contact reactions and a decrease in complete response rate. The gel formulation has a complete response rate of 13.8%, which is a decrease in efficacy when compared to aqueous-based preparations of similar concentrations.