Background Chronic occupational exposure in textile workers lowers the pulmonary function and levels of sinonasal IgA. A Nephrolepis exaltata herbal mask can protect the respiratory tract. This study aims to understand the effect of this herbal mask on the IgA levels and pulmonary function in textile workers. Thirty employees were selected for this study. Methods The pre- and post-test randomized experimental control trials were conducted in a garment industry of Bawen, Semarang, Indonesia. The subjects that qualified to participate (n = 30) fulfilled the inclusion criteria i.e., 20–35 years old, healthy, and willing to be a research subject; and exclusion criteria i.e., having history of alcohol consumption, smoking, history of liver disease, autoimmune disease, cancer, pulmonary and heart disease and/or being pregnant. The subjects were then divided randomly into control group (n = 15), who used regular mask that was rewashed and changed every month for eight weeks, and treatment group (n = 15), who used Nephrolepis exaltata mask that was changed every two days for eight weeks. Pulmonary function tests were carried out using MIR Spirolab III before and after the experiment. IgA levels were measured by nasal wash method using ELISA. Results IgA levels of the treatment group before and after usage of mask were significantly different (p<0.001) compared to the control group. There were significant difference in FVC of the control group, but no significant difference was observed for FEV1 (p = 0.507) and PEF (p = 0.001). In the treatment group, all three parameters showed significant differences [FVC (p = 0.038), FEV1 (p = 0.004), and PEF (p = 0.001)]. The means of ΔFVC, ΔFEV1, and ΔPEF were significantly (p<0.05) higher in the treatment group with OR = 5.1 for higher IgA levels. Conclusions The herbal mask is better in increasing IgA and improving the pulmonary function compared to the regular mask.