The transport characteristics and the subsequent reduction in mechanical strength of natural rubber vulcanizates have been investigated using chlorinated hydrocarbons as probe molecules. The transport process has been examined by a sorption-desorption-resorption-redesorption technique. The mode of transport was found to change from the anomalous nature to the regular Fickian trend after a sorption-desorption cycle. The modulus of rubber samples decreased considerably under swollen conditions. The marching trend of stress-strain curves vanished after solvent saturation which has been explained on the basis of the absence of strain-induced crystallisation in swollen specimens. The modulus of solvent-saturated samples was found to be a function of rubber-solvent interaction which has been explained in terms of the differences in the contribution of physical entanglements to the total crosslink density.