Background Systematic analysis of the determinants of choice of a treatment modality aids to the understanding of decision process of healthcare utilization. The revealed preference of a single modality may differ according to the nature of disease. Existing studies have not integrated possible causal factors in a model with respect to diseases. This study identifies major determinants and formulates their integral effect on choice of a particular modality on acute and chronic diseases in accordance to socio-behavioural model. Methodology A cross-sectional study on 300 samples using a 30-point questionnaire, developed in Likert scale and dichotomous scale. Possible determinants are tested on choice of CAM in case of acute disease and of chronic disease separately. Results Revealed single modality treatment preference (of CAM) varies widely between acute disease (13%) and chronic disease (58.67%). Bivariate associations are significant for gender (For, overall CAM preference, p=0.001, acute disease, p<0.001, chronic disease, p=0.024), Disease burden (overall and chronic: p<0.001, acute: p=0.008) and previous CAM usage (overall and chronic: p<0.001, acute: p=0.016). Social factor individually has significant influence on choosing CAM both acute (OR=1.096, p<0.001) and chronic disease (OR=1.036, p<0.001). Ideation of philosophical need factor, guided by philosophical congruence with CAM (OR=1.047, p<0.001) is a novel finding of this study. While with multiple logistic regression male gender (p=0.03), social factor (p<0.001), perception of CAM efficacy (p=0.02) and negative ideation about CAM cost-effectiveness (p=0.002) are found to be important in Acute disease; choosing CAM in chronic disease is guided by female gender (p=0.001), making decision in-group (p=0.001), low disease burden (p<0.001), philosophical need factor (p=0.001), and perception of CAM efficacy (p<0.001). Conclusion Demographic, social, cognitive and philosophical factors are important determinants of choosing CAM as a treatment modality over conventional medicine, but they act differently on CAM preference in acute and chronic diseases.