Main adverse events of Roflumilast are weight loss, loss of appetite, insomnia, headache, diarrhea, vomiting, and nausea. Although the majority of these adverse reactions were mild or moderate. They occurred mainly at the beginning of therapy and mostly resolved with continued treatment around for two weeks according to experiences of clinicians. These adverse events occur more often in Roflumilast 500 μg than 250 μg, having negative impact on compliance of patients at the early stage of treatments.