<p>While the Brazilian rubber tree has traditionally been the primary source of natural rubber, growing environmental concerns and cultivation challenges have spurred interest in alternative sources. Research into harvesting rubber from herbaceous plants like dandelions and lettuce is ongoing, but low rubber yields and complex extraction processes pose significant obstacles. To address these challenges, the development of high-yield rubber-producing organisms and accurate methods for quantifying rubber content are essential. This study introduces an infrared spectroscopy-based method for the quantitative analysis of rubber content in plant latex. This method offers simplicity and precision, enabling the screening of various plant species as potential rubber sources. By targeting specific infrared peaks characteristic of natural rubber and constructing a standard curve, we successfully quantified rubber content in both <i>Ficus elastica</i> (Indian rubber tree) and <i>Lactuca sativa</i> (lettuce). Our findings demonstrate the feasibility of using this method to rapidly screen a wide range of plant mutants for enhanced rubber production, contributing to the development of sustainable and renewable rubber sources.</p>