The present disclosure relates to a method and system for determining drug intake by subject by monitoring gestures of subject by gesture monitoring system. The gesture monitoring system receives plurality of sensor data from registered device worn on finger of both hands of a subject, determine parameters from plurality of sensor data, comprising magnitude change, turn angle change, direction change and time difference between consecutive samples of plurality of sensor data, determines one or more events associated with finger of both hands of subject by comparing parameters with pre-defined range of turn angle change, direction change and time difference, correlate one or more events of finger of both hands occurring at same time duration using predefined rules to identify sequences of intermediate gestures and identify one or more final gestures by correlating one or more sequences of intermediate gestures using the pre-defined rules for determining drug intake by subject.
