Background: Complementary and alternative medicines (CAM), such as herbal remedies, are widely used by patients with chronic diseases, such as asthma. However, it is unclear whether use of the herbal remedies is associated with decreased adherence to inhaled corticosteroids (ICSs), a key component of asthma management. Objective: To examine the association among use of herbal remedies, adherence to prescribed ICSs, and medication and disease beliefs. Methods: We surveyed 326 adults with persistent asthma who received care at 2 inner-city outpatient clinics. Patients were asked about CAM use (teas, herbs, and rubs) for the treatment of asthma in the prior 6 months. Medication adherence was assessed using the Medication Adherence Report Scale, a validated self-report measure. Univariate and multiple regression analyses were used to assess the relationship among herbal remedy use, adherence to ICSs, and medication and disease beliefs. Results: Overall, 25.4% (95% confidence interval, 20%-30%) of patients reported herbal remedy use. Univariate analyses showed that herbal remedy use was associated with decreased ICS adherence and increased asthma morbidity. In multivariable analysis, herbal remedy use was associated with lower ICS adherence (odds ratio, 0.4; 95% confidence interval, 0.2- 0.8) after adjusting for confounders. Herbal remedy users were also more likely to worry about the adverse effects of ICSs (P = .01). Conclusions: The use of herbal remedies was associated with lower adherence to ICSs and worse outcomes among inner-city asthmatic patients. Medication beliefs, such as worry about ICS adverse effects, may in part mediate this relationship. Physicians should routinely ask patients with asthma about CAM use, especially those whose asthma is poorly controlled.