Abstract
Background/Objectives: We evaluated whether herbal steam bath (HSB) added to standard care improved persistent symptoms following COVID-19. Methods: Sixty-eight adults were randomized equally to HSB plus standard care or standard care alone. Outcome assessors were blinded; participants and providers were unblinded. Eligibility was two weeks to six months after a negative SARS-CoV-2 test, without requiring WHO-defined post-COVID-19 condition. The HSB regimen was scheduled three times weekly for four weeks. Each session comprised three 10-min periods of herbal steam exposure, totaling 30 min of exposure. The primary outcomes were Fatigue Severity Scale (FSS) scores and seven symptom ratings at Week 4. Secondary outcomes included peak expiratory flow rate (PEFR), functional status, dyspnea grade, oxygen saturation, and vital signs. Continuous outcomes were compared using baseline-adjusted models; the seven symptom comparisons were adjusted for multiplicity using Holm’s method. Results: The adjusted between-group difference in FSS was −0.80 points (95% CI, −1.56 to −0.04; p = 0.040); a change-score sensitivity analysis did not reach statistical significance (p = 0.114). All seven symptom ratings favored HSB after Holm adjustment within the symptom family. Among secondary outcomes, the adjusted PEFR difference was 29.52 L/min (95% CI, 12.22 to 46.82; p = 0.001), and Post-COVID-19 Functional Status (PCFS) and modified Medical Research Council (mMRC) grades favored HSB; SpO2 did not differ. No adverse events were reported throughout the study. Conclusions: HSB plus standard care was associated with lower symptom scores and higher PEFR than standard care alone, while the FSS finding remained inconclusive. These preliminary findings support further investigation of the complete HSB intervention.