We present the case of a healthy 76-year-old man with a whitish, hyperkeratotic lesion of the lower lip diagnosed as actinic cheilitis (AC) previously treated with classic red light photodynamic therapy 5 years ago. Initial treatment with 5% imiquimod cream - also with intensified application - failed. After 2 cycles thrice daily, consecutive applications of 150 μg/g ingenol mebutate gel at 3 weeks' interval, the lesions cleared completely. Surprisingly, no pustular or crusting reaction or other side effect occurred contrary to expectation. Remission was stable for 10 months, when recurrence occurred. Ingenol mebutate proved to be a feasible and safe treatment in this otherwise refractory case of AC.