This paper investigates the shielding effectiveness of natural polymers, such as natural rubber and cotton, against space radiation. The results are compared with those of conventional shielding materials, such as polyethylene, Kevlar, and polycarbonate. Monte Carlo simulations were performed using a Geant4-based tool, Multi-layered shielding simulation software (MULASSIS). The shielding properties were studied using proton, alpha, and iron ions with energies of 1 GeV/n. Online Tool for the Assessment of Radiation in Space (OLTARIS) is used for calculating the effective dose equivalent for the GCR spectra. Both studies showed that the natural polymers are just as effective as conventional space radiation shielding materials in terms of dose reduction. Natural rubber is found to be the most effective among the natural polymers. For 50 g/cm2 aluminum with 20 g/cm2 layer of chosen materials configuration, the effective dose equivalent values (mSv/day) for Polyethylene, Kevlar, Polycarbonate, Kapton, Epoxy, Dacron, and Vectran were 0.93, 1.08, 0.995, 1.056, 1.007, 1.031, and 1.042, respectively. The effective dose equivalent values (mSv/day) for natural polymers (natural rubber, cotton, jute, and silk) under the same conditions were 0.95, 1.004, 1.036, and 1.004, respectively. The challenges of utilizing radiation shields made of natural polymers are also briefly covered.