Rhubarb is used primarily as a tart ingredient in pies, jams, and sauces, but it also has a long history in traditional medicine as a natural laxative and digestive aid. Beyond the kitchen and medicine cabinet, rhubarb leaves (which are toxic to eat) have practical household uses like cleaning metal. The plant is more versatile than most people realize.
Cooking With Rhubarb
Rhubarb’s sharp, sour flavor makes it a natural partner for sugar, which is why it shows up most often in desserts. Pies are the classic use, especially strawberry-rhubarb pie, but rhubarb also works in compotes, crumbles, puddings, and fruit syrups. In Germany, a traditional dessert called rote grütze cooks rhubarb with other red fruits into a thick pudding served with cream.
The stalks aren’t limited to sweets. Quick-pickled rhubarb with lemongrass and ginger makes a tangy condiment that pairs well with rich meats and fish. Rhubarb syrups are used in cocktails and nonalcoholic drinks like ginger-rhubarb coolers. You can even juice it: blended with water, rhubarb produces a bright pink juice with an intensely tart flavor.
One stalk of rhubarb (about 51 grams) contains only 11 calories and provides 1 gram of fiber and 5 milligrams of vitamin C. It’s mostly water and fiber, making it a low-calorie way to add bold flavor to dishes.
Rhubarb as a Natural Laxative
Rhubarb root has been used as a laxative for centuries, and modern research has identified why it works. The root contains compounds called anthraquinones that act on the colon in two ways. First, they reduce the colon’s ability to absorb water, keeping stool soft. Second, they stimulate the gut to increase motility, the muscular contractions that move food through your digestive tract. One specific compound, sennoside A, triggers immune cells in the colon wall to release signaling molecules that slow water absorption.
This is the same mechanism behind over-the-counter senna-based laxatives. Rhubarb root, known as “da huang” in Traditional Chinese Medicine, has been prescribed for constipation and broader digestive problems for thousands of years. In Chinese hospitals, it is still used to support gastrointestinal function in critically ill patients. The stalks you buy at the grocery store contain far lower concentrations of these compounds than the root, so eating rhubarb pie won’t have a strong laxative effect.
Cholesterol and Heart Health
Rhubarb fiber appears to help lower cholesterol through a simple mechanism: it binds to bile acids in the gut. Your body makes bile acids from cholesterol, so when rhubarb fiber traps them and carries them out, your liver pulls more cholesterol from the blood to make replacements. This process reduces circulating levels of LDL cholesterol and triglycerides.
Animal studies have shown that rhubarb extracts can lower LDL cholesterol, triglycerides, and total cholesterol while raising HDL (the protective kind). Some of this effect comes from compounds that appear to inhibit cholesterol production in the liver and promote cholesterol excretion through the intestines. Rhubarb also contains resveratrol, the same compound found in red wine, which has demonstrated lipid-lowering effects in lab settings. Human clinical trials are limited, so these findings are promising but not yet definitive.
Antioxidant Content
Red rhubarb stalks get their color from two anthocyanins, the same type of pigments found in blueberries and cherries. The deeper the red color, the higher the antioxidant content tends to be. Testing across multiple rhubarb varieties found a nearly threefold difference in antioxidant capacity between the weakest and strongest varieties, with deeply red cultivars like Valentine scoring highest.
Beyond anthocyanins, rhubarb stalks contain quercetin, rutin, and small amounts of resveratrol. These polyphenols act as antioxidants in the body, helping neutralize molecules that damage cells. Rhubarb won’t compete with blueberries as a concentrated antioxidant source, but for a vegetable most people treat as a fruit, it carries a surprisingly diverse mix of protective plant compounds.
Oxalic Acid and Leaf Toxicity
Rhubarb leaves are poisonous due to extremely high concentrations of oxalic acid and should never be eaten. The stalks contain oxalic acid too, but at much lower levels that are safe for most people. Across 78 cultivars tested in one study, oxalate content in the stalks ranged from 3.35% to 9.48% of dry matter. Interestingly, stalk color doesn’t predict oxalate levels. Red, green, and pink varieties showed no consistent pattern, and forced (indoor-grown) rhubarb didn’t differ from field-grown in oxalate content. Older stalks tend to accumulate more oxalic acid than younger ones.
If you’re prone to kidney stones, especially calcium oxalate stones, you may want to limit rhubarb intake. Cooking rhubarb and discarding the liquid can reduce some of the oxalate content, though it won’t eliminate it entirely.
Non-Food Uses
Those toxic leaves aren’t entirely useless. The high oxalic acid concentration that makes them dangerous to eat also makes them effective for cleaning aluminum pots and other metal containers. Rubbing the leaves on tarnished metal or simmering them in a stained pot can dissolve mineral buildup and restore shine. Rhubarb leaves have also been used traditionally in tanning animal hides, where the oxalic acid helps break down and preserve the leather.
Selecting and Storing Fresh Rhubarb
Look for stalks that are firm, straight, and free of blemishes. The best commercial grade has stalks thicker than one inch and longer than ten inches, with good color and no pithiness. Avoid stalks that feel soft or spongy, since rhubarb has a porous interior that allows bacteria to enter through damaged spots.
Fresh rhubarb keeps two to four weeks in the refrigerator when stored near 32°F with high humidity. For longer storage, chop the stalks into pieces and freeze them. They’ll lose some texture when thawed but work perfectly in cooked applications like pies, sauces, and compotes. Rhubarb season runs from April through June in most regions, so freezing is the best way to enjoy it year-round.