A fluid delivery system for delivering a bolus dose of therapeutic fluid into the body of a user, the system comprising: a pump for delivering therapeutic fluid into the body; and at least one processor including instructions operating thereon, the processor being configured to: receive a current blood glucose level of the user; receive a BG trend of the user, including a direction and/or rate of change of blood glucose level of the user; receive one or more first additional parameters relating to the user; receive one or more second additional parameters relating to the user, the one or more second additional parameters being selected from a group consisting of physical activity level, emotional stress level, blood ketones level and/or trend, blood pH level and/or trend, presence of an illness and/or menstruation and body temperature; and determine a bolus dose based on the CBG, the BG trend, the one or more first additional parameters relating to the user and the one or more second additional parameters, such that delivering the bolus dose to the user compensates for a change in a BG level of the user wherein the processor includes instructions configured to: determine an initial bolus dose based on the one or more first additional parameters relating to the user and the CBG; and determine the bolus dose based on the initial bolus dose being multiplied by one or more multiplier values or an average of a plurality of multiplier values, the or each multiplier value representing a magnitude of a particular user parameter on a relative scale, the one or more multiplier values including at least one of: a multiplier value correlating to the BG trend; and a multiplier value correlating with at least one of the one or more second parameters. a pump for delivering therapeutic fluid into the body; and at least one processor including instructions operating thereon, the processor being configured to: receive a current blood glucose level of the user; receive a BG trend of the user, including a direction and/or rate of change of blood glucose level of the user; receive one or more first additional parameters relating to the user; receive one or more second additional parameters relating to the user, the one or more second additional parameters being selected from a group consisting of physical activity level, emotional stress level, blood ketones level and/or trend, blood pH level and/or trend, presence of an illness and/or menstruation and body temperature; and determine a bolus dose based on the CBG, the BG trend, the one or more first additional parameters relating to the user and the one or more second additional parameters, such that delivering the bolus dose to the user compensates for a change in a BG level of the user receive a current blood glucose level of the user; receive a BG trend of the user, including a direction and/or rate of change of blood glucose level of the user; receive one or more first additional parameters relating to the user; receive one or more second additional parameters relating to the user, the one or more second additional parameters being selected from a group consisting of physical activity level, emotional stress level, blood ketones level and/or trend, blood pH level and/or trend, presence of an illness and/or menstruation and body temperature; and determine a bolus dose based on the CBG, the BG trend, the one or more first additional parameters relating to the user and the one or more second additional parameters, such that delivering the bolus dose to the user compensates for a change in a BG level of the user determine an initial bolus dose based on the one or more first additional parameters relating to the user and the CBG; and determine the bolus dose based on the initial bolus dose being multiplied by one or more multiplier values or an average of a plurality of multiplier values, the or each multiplier value representing a magnitude of a particular user parameter on a relative scale, the one or more multiplier values including at least one of: a multiplier value correlating to the BG trend; and a multiplier value correlating with at least one of the one or more second parameters. a multiplier value correlating to the BG trend; and a multiplier value correlating with at least one of the one or more second parameters.