CONTEXT: Complementary and alternative medicines (CAMs) are extensively used by the public. Noncompliance is an important cause of therapy failure. AIM: This study was done to determine prevalence of emergency admission due to noncompliance with modern medicine following switching over to CAM and to identify any significant association for CAM use among noncompliers. SETTING AND DESIGN: This cross-sectional study was conducted in the emergency unit of a tertiary healthcare institute. MATERIALS AND METHODS: Demographic factors and system affected were compared between compliers and noncompliers. Prevalence, reasons and nature of noncompliance were determined. Age, gender, outcome, relation strength and potential preventability of noncompliance, precipitating and previous disease and noncompliant drugs were compared for significant association between CAM using and other noncompliers. STATISTICAL ANALYSIS: Student's 't' test, Chi square test and odds ratio were used. RESULTS: Of the 506 patients interviewed 168 (33%) were noncompliant. In 160 (95%) patients noncompliance was due to under-dosing. Lack of knowledge and CAM use constituted 144 (86%) noncompliance-related admissions. Thirty-three (7%) admissions were strongly related to noncompliance and CAM use. Age, gender, outcome, drug use and diseases except chronic obstructive pulmonary disease (COPD) and asthma showed no association while relation strength and potential preventability of emergency admission was less with CAM-using noncompliers. Noncompliance was observed for hypertension, diabetes, COPD and asthma, seizure disorder, tuberculosis and hemophilia besides hepatic and renal failure. The CAM noncompliers used CAM more for modern medicine incurable or unaffordable than curable diseases. CONCLUSION: Advice for regular treatment and frequent monitoring can decrease CAM use-related noncompliance admissions.