Abstract Background: The main biological activities of cannabis are due to the presence of several compounds known as cannabinoids. Delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are two of the main cannabinoids. Studies have shown that the efects of THC can be modulated by CBD. Objective: This study aims to look at the efect of diferent concentrations of THC and CBD separately and in combination, on blood viscosity, elasticity and membrane integrity. Methods: Blood samples were collected from twenty-four healthy adult non-smokers. Blood viscosity and elasticity were determined using the Vilastic Scientifc Bioprofler for diferent concentrations (0, 2.5, 25, 50 and 100ng/ml) of CBD and THC...