Cannabis Roots Hold Untapped Medical Potential, Review Finds

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Every cannabis harvest ends the same way: the roots get yanked out of the pot or the soil, tossed in the green waste bin, and forgotten. Cultivators have been doing this for decades without a second thought, because everything valuable in the plant was assumed to live up top, in the flowers and the resin-coated trichomes that make THC and CBD. A new review published in the Journal of Cannabis Research is asking why nobody bothered to check what's actually in the part growing underground.

Researchers from the University of Santa Cruz Do Sul and the Federal University of Rio Grande in Brazil combed through eight scientific databases looking for every study on cannabis root extracts and isolated root compounds published through December 2024. Their conclusion is straightforward: the root system contains a genuinely diverse set of bioactive molecules that has never gotten the scrutiny routinely applied to flower, and that gap looks increasingly hard to justify as an accident of habit rather than science.

The timing isn't incidental. Legal cannabis cultivation has scaled up dramatically across North America and parts of Europe over the past decade, and every plant pulled from the ground leaves behind a root mass that mostly gets composted or discarded outright. If that biomass turns out to hold compounds worth extracting, growers are currently throwing away a byproduct with potential value, purely because the industry never looked closely enough to know better.

What the Review Actually Found

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The Brazilian team didn't run new lab experiments on root chemistry themselves. Instead, they systematically gathered and synthesized existing published research on what compounds show up in cannabis roots and what those compounds do in cell and animal models. That distinction matters: this is a review paper, meaning its value comes from pulling together a scattered, thin body of prior work into one coherent picture rather than generating fresh data.

What that picture shows is a plant part with real chemical complexity. The researchers identified several distinct compound classes present in cannabis roots, including phytosterols, alkaloids, terpenes, and phenolic compounds, alongside only trace amounts of cannabinoids. Named compounds turning up across the studies include beta-sitosterol and stigmasterol, both plant sterols with documented anti-inflammatory activity in other contexts, plus friedelin and friedelanol, triterpenoids that show up in various medicinal plants. There's also cannabisativine, an alkaloid essentially unique to cannabis roots, and vanillin, the compound that gives vanilla its flavor and has its own antioxidant properties. Trace cannabidiol (CBD) and cannabichromene (CBC) were also detected, confirming the roots aren't entirely devoid of cannabinoids, just very low in them compared to flower.

The authors frame this collection as a valuable source of pharmacologically active molecules with real potential for therapeutic development, language that's notably more assertive than the typical hedge found in review papers. It's worth being clear-eyed about what that claim rests on, though: a compilation of prior lab findings, not a new clinical dataset. The review's real contribution is showing that enough scattered evidence already exists to justify treating roots as a legitimate research target rather than a discard product.

Inflammation and Pain: What the Underlying Studies Show

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The most consistent finding across the studies the review pulled together involves inflammation. Multiple lab experiments using root extracts and isolated root compounds reported reductions in inflammatory markers including interleukin-6 (IL-6), interleukin-1 beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha), three signaling molecules that drive inflammatory response throughout the body and show up as targets in everything from arthritis research to autoimmune drug development.

Pain-related findings follow a similar pattern. In one animal study, an aqueous extract made from cannabis roots reduced the number of abdominal contractions mice exhibited in response to a standard pain-inducing chemical stimulus, a common test researchers use to screen for analgesic activity before moving to more sophisticated pain models. The same extract also increased how long the mice tolerated a heated surface before pulling away or licking their paws, a test known as the hot plate assay that's used across pharmacology to gauge pain threshold. Longer tolerance times suggest the extract was doing something to blunt the animals' pain response, not just sedating them generally.

A separate study published in BMC Complementary Medicine and Therapies in early 2026 added mechanistic detail, finding that a specific fraction isolated from cannabis roots showed strong antioxidant and anti-inflammatory activity linked to modulation of the CB1 and CB2 cannabinoid receptors, alongside elevated levels of 2-AG, an endocannabinoid the body produces naturally. That's a more specific biological story than compounds affecting inflammation.

None of this has been tested in humans. These are cell cultures and mouse models, the first rung on a long ladder that most compounds never finish climbing.

Why Roots Have Been Ignored This Long

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It's worth asking why this took so long, because the neglect wasn't really scientific caution, it was a byproduct of where the money and attention went. Cannabis breeding programs for the better part of a century have optimized almost exclusively for flower: higher THC, denser trichome coverage, particular terpene profiles for smell and flavor. Roots contain only small concentrations of cannabinoids, so researchers largely assumed decades ago that they weren't worth studying and moved on. That assumption calcified into a default nobody revisited.

The economics of legalization have made the oversight harder to ignore. A 2024 review noted that after Canada legalized recreational cannabis in 2018, the volume of root-related plant waste rose sharply as commercial-scale cultivation ramped up, with roots accounting for roughly 30% of total harvested plant biomass at some operations. That's not a trivial side stream. It's close to a third of the plant, generated at industrial scale, going straight into waste management.

Federal restrictions in the United States compounded the problem from the research side. Cannabis's Schedule I status has made it difficult for decades to obtain research-grade plant material and funding for whole-plant studies of any kind, let alone studies focused on an underground plant part nobody thought was interesting anyway. That regulatory friction slowed basic botanical research on cannabis generally, and roots sat near the bottom of the priority list.

Notably, this isn't entirely new territory. Traditional and folk medicine practices in various cultures have used cannabis root preparations, often boiled or crushed into poultices, to treat inflammation, pain, and wound care long before any modern lab took an interest. Modern science is, in a sense, catching up to something older healing traditions already suspected.

What Comes Next for Root Research

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The review's authors close by calling for renewed scientific attention to what they describe as an underexplored pharmacognostic resource, essentially arguing that cannabis roots deserve to be treated as a legitimate target for drug discovery rather than an afterthought. Pharmacognosy, the study of medicines derived from natural sources, has a long history of finding useful compounds in plant parts nobody expected, and the authors are betting roots could be cannabis's next example.

The gap between that ambition and an actual treatment is wide. No human clinical trials on cannabis root extracts exist yet. Every finding referenced in the review comes from cell cultures or animal models, which is standard for early-stage pharmacological research but means any therapeutic claim right now is preliminary by definition, not a preview of a product that's coming soon.

There's a commercial angle layered underneath the science, though. If root biomass currently treated as cultivation waste turns out to be a viable source of extractable, sellable compounds, growers have an obvious incentive to stop discarding it and start finding buyers for it instead. That kind of shift has happened before in agriculture, where byproducts once dumped or burned become revenue streams once someone figures out what's in them.

Anyone interested in this space should keep in mind that the regulatory status of cannabis plant parts, roots included, varies significantly by state and by country, and any future commercial root-derived product would have to navigate the same fragmented legal landscape that already governs flower, extracts, and other derivatives. For now, cannabis root extracts belong in the research column, not the available-treatment column, and readers should check their local laws before assuming any root-based product is legal to buy, sell, or possess where they live.

None of this proves cannabis roots do anything meaningful for a human being with real pain or real inflammation. What the review does establish is harder to dismiss: an entire part of a heavily studied plant has gone essentially unexamined for reasons that trace back to habit and convenience rather than any real scientific verdict that it wasn't worth the trouble.

That neglect is getting more expensive to maintain. As legal cultivation operations scale up across more states and countries, the volume of root biomass heading straight to the compost pile scales up right along with it. There's now a practical economic argument sitting on top of the scientific one, and it's the kind of argument that tends to get research funded faster than curiosity alone ever does.

Don't expect a root-derived cannabis product on dispensary shelves anytime soon. Identifying interesting compounds in a lab is the easy part of this process. The real bottleneck, as it is for nearly every promising preclinical finding in medicine, is the years of human clinical trials required to establish that something safe and effective in a mouse actually works the same way in a person. This will stay a research story, worth watching but not worth acting on, for a good while yet.