The manufacture and consumption of personal protective equipment such as medical masks and gowns, and the associated plastic waste are now looming as an environmental challenge in terms of the disposal of these plastic wastes. This calls for innovative and sustainable approaches to dealing with such challenges. Accordingly, this research aims at developing environmentally sustainable options while boosting the efficient utilisation of plastic waste in the concrete industry. This paper presents the results of an experimental investigation on evaluating the influence of polypropylene-based fibres obtained by shredding medical face masks and gowns on the flexural performance of reinforced concrete members. The experimental programme comprised flexural tests on thirty notched prismatic specimens, and twelve full-scale reinforced concrete beams containing varying amounts of fibre content (0, 0.25%, and 0.5%). Tests for mechanical properties indicated no significant influence of fibres on the compressive strength and a 23% increase in the tensile strength with 0.25% fibres. A 19% reduction in the instantaneous deflection of beams due to the addition of fibres was also observed. Moreover, the cracking load capacity of FRC beams increased by up to 40%. Comparison of the experimentally obtained deflections with those predicted using the models in ACI Committee 544 and 318, Eurocode 2, and models by other researchers indicated that codes predicted the deflection in beams without masks with reasonable accuracy. However, those models overestimated the deflection in beams containing fibres. DIANA software was used to conduct a finite element analysis of fibre-reinforced concrete beams. Results obtained from the nonlinear analysis considering the post-cracking behaviour of FRC members showed a good correlation with the experimental results.