Larix sibirica is a conifer and a renewable source of chemically diverse constituents with pharmacological uses. This review examines its phytochemical composition, extraction strategies, and reported pharmacological activities, including preliminary studies of arabinogalactan-based drug carriers and sulfated lignins. The compiled database comprised 354 records representing 232 unique compounds reported in 25 publications, distributed among 16 phytochemical groups and 12 plant-source categories. Phenolics, terpenoids, lipids, arabinogalactan and lignans were concentrated unevenly across bark, needles, oleoresin, wood, knotwood and heartwood resin. Extraction remained dominated by conventional solvent partitioning, Soxhlet extraction, steam distillation and chromatography; aqueous ethanol enabled simultaneous recovery of arabinogalactan and taxifolin, but direct comparisons with intensified technologies were lacking. Antioxidant activity was supported mainly by chemical assays, whereas antiviral, antibacterial, neuritogenic, anti-inflammatory and anti-allergic effects relied predominantly on cellular or limited animal models. Arabinogalactan showed immunomodulatory and intestinal barrier effects and was investigated as a preclinical drug carrier, while sulfated lignins showed concentration-dependent effects in in vitro blood-compatibility assays. Nevertheless, heterogeneous preparations, inconsistent measurement bases and limited dose–response, pharmacokinetic and toxicological data restrict cross-study comparison and clinical interpretation. Future work should prioritize standardized sampling and extracts, validated quantitative LC-MS/MS and GC-MS methods, untargeted metabolomics, bioactivity-guided fractionation, controlled in vivo studies and systematic safety assessment. These advances are required to convert descriptive phytochemistry into reproducible evidence for therapeutic and industrial development.