Background: Asthma is a disease that causes a lot of suffering. It becomes a hurdle in everyday life. Asthma self-care program through mobile Line application (SALA) might be a good choice to help resolving this problem.

Objective: To evaluate effectiveness of SALA program among asthma patients.

Materials and Methods: The present study was a randomized controlled trial. The study sample consisted of 62 participants aged between 20 to 60 years with mild to moderate asthma. The study sample were randomly assigned to intervention plus usual care (intervention group, n=31) or usual care (control group, n=31) by computer generated. SALA program was sent to participants once a week for two months through their mobile phone, drug reminder appointment date for four months. The study period was six months. Clinical record form and Questionnaire were adapted to collect the demographic data and lung function via spirometer as FEV₁, FVC, FEV₁/FVC, PEFR, ACS, knowledge, attitude, and self-management. Mini Asthma Quality of Life (QOL) questionnaire was used to collect the data. Intention to treat (ITT), Repeated ANOVA, and General Linear model were statistical technique used to analyze the data.

Results: Data from 60 asthma patients were available for analyses. The baseline characteristics of both groups were not significantly different. There were statistically significant mean differences in between the groups at three and six months. The mean difference in the following variables were FEV₁ 13.83 (5.01 to 22.65) FVC, 13.36 (2.62 to 24.09) FEV₁/FVC, 11.65 (4.8 to 18.49), PEFR 9.85 (0.03 to 19.67), ACS 2.45 (0.62 to 4.27), knowledge 2.64 (0.81 to 4.46), and self-management 4.26 (2.00 to 6.52).

Conclusion: SALA improved knowledge, self-management, asthma status, and lung function among asthma patients.