Objectives: To determine the prevalence, patterns and correlates of medicinal herb use in a rural Iranian population and to evaluate demographic and clinical predictors using adjusted regression models.

Design: Cross-sectional analysis of baseline data from the Fasa Prospective Epidemiological Research Studies in Iran Cohort Study.

Setting: Sheshdeh, a rural district in southern Iran.

Participants: 10 143 adults aged 35-70 years enrolled between 2017 and 2019.

Primary outcome measures: Prevalence of self-reported medicinal herb use during the past year and its associations with demographic variables and non-communicable diseases (NCDs).

Results: Overall, 84.7% of participants (95% CI 83.9% to 85.5%) reported herb use. In multivariable logistic regression, higher educational attainment was positively associated with herb use (university education vs. illiterate: adjusted OR 1.41, 95% CI 1.11 to 1.88). No significant adjusted associations were observed between herb use and major NCDs including diabetes, hypertension, ischaemic heart disease or depression. The most frequently used herbs were Zataria multiflora, Echium amoenum and Matricaria chamomilla, most commonly for anxiety/neurasthenia (81.6%), gastric pain (59.6%) and common cold (49.8%).

Conclusions: Medicinal herb use is highly prevalent among adults in southern Iran. Educational level, but not chronic disease status, was associated with herb use. These findings highlight the need for integrated public health strategies regarding safe and evidence-based use of medicinal herbs.