The current research examines the effect of performance expectancy (PE), effort expectancy (EE), social influence (SI), facilitating condition (FC), and anxiety (AX) influencing the consumer’s behavior intention (BI) and measuring action (MA) towards the use of digital marketing for purchasing medical nutrition product. The outcome of this study is obtained through an online survey conducted by distributing a structured questionnaire through social media and e-commerce platforms using convenience and snowball sampling techniques in Colombo and Kandy, Sri Lanka. In total, there were 204 data of patients or caregivers and medical nutrition users which were analyzed employing descriptive statistics, Exploratory Factor Analysis, and Structural Equation Modeling. The result of the analyses shows that performance expectancy (PE) and effort expectancy (EE) has a positive and significant effect, while anxiety (AX) has a negative and significant effect on behavioral intention (BI) to adopt digital marketing for purchasing medical nutrition. Additionally, social influence (SI) and facilitating conditions (FC) do not have a significant effect on behavioral intention (BI). The study also found that BI does not have a mediating effect in the relationship between performance expectancy, effort expectancy, anxiety, and measuring action. UTAUT is useful for understanding consumers to use digital marketing for increasing their awareness about medical nutrition. This research would encourage the use of digital marketing platforms by medical nutrition providers to solve malnutrition problems.