Although there was no significant association of MDR1 C3435T polymorphism between two groups of patients and healthy controls, our data showed a substantial association of CC genotype with the development of several clinical features, including erythema nodosum (P = 0.001, OR = 2.686, 95%), pseudofolliculitis (P = 0.002, OR = 2.812, 95%), and skin lesions (P = 0.040, OR = 1.934, 95%).