A 40-year-old woman presented with a delusion of warts on the forehead, for which she was applying podophyllin toxin. A skin biopsy was taken, which showed prominent mitotic figures in the basal and suprabasal layers of the epidermis and apoptotic keratinocytes. Histopathologically Bowen's disease was suspected, but was discounted after clinicopathological correlation was obtained and showed absence of epidermal atypia or disorganization. This case demonstrates the histological resemblance of podophyllin reaction to Bowen's disease. Differentiation of self-inflicted from organic skin disease may be difficult, especially where histopathological findings are confounded by cutaneous application of toxins.