This is a randomized control trial evaluating the efficacy of zanthoxylum nitidum tincture on preventing progression of paronychia caused by afatinib from grade 1 to grade 2/3. Enrolled participates will randomly receive original treatment or original treatment plus zanthoxylum nitidum tincture immersion of the sick nail(s).

Inclusion Criteria:

1. Pathologically or cytologically confirmed non-small cell lung cancer；
2. Undergoing treatment with afatinib；
3. With grade 1 paronychia；
4. Age between 18 to 80 years old；
5. Estimated life expectancy of more than months；
6. With the written informed consent.

Exclusion Criteria:

1. Paronychia before afatinib treatment;
2. Grade 2 or severer paronychia;
3. Stop using afatinib or with reduced dose of afatinib;
4. Currently diagnosed with severe encephalopathy or psychiatric disorders affecting patients ability of self expression.
5. Has other legal, medical or ethical reasons that patients are not appropriate for clinical study.