Benefits
Bowel regularity and softer stools with dried whole root
In a placebo-controlled trial in 55 adults aged 40 to 75 at raised risk of high blood sugar, dried chicory root (15 g a day, then 30 g a day for 3 weeks) raised stool frequency from 1.3 to 1.9 a day while the maltodextrin group stayed near 1.3, and stools softened more than on placebo. These were secondary outcomes; the main blood sugar outcomes did not change. The maker supplied the product.
Gut bacteria and short-chain fatty acids
In the same trial, Bifidobacterium and butyrate-producing Anaerostipes rose to about three times placebo levels, and total fecal short-chain fatty acids rose about 26% in the root group, a significant difference from placebo, all returning to baseline within 2 weeks of stopping. A 12-week trial of the same root product found similar bacterial shifts. These are gut markers, not health outcomes.
Insulin sensitivity with dried whole root over 12 weeks
In a small trial of 35 adults aged 45 to 70 with excess weight and insulin resistance, 30 g a day of dried chicory root for 10 weeks (after 2 weeks at half dose) raised whole-body insulin sensitivity on a clamp test and lowered triglycerides versus a puffed millet placebo, both secondary outcomes. The main outcome, peripheral insulin sensitivity, only trended (p = 0.085), and body weight did not change.
Blood sugar markers with a roasted root drink
In a small trial of 47 healthy Japanese adults, a roasted chicory root drink (300 mL a day, about 0.75 g inulin) for 4 weeks lowered HbA1c by 0.09 points versus 0.03 on a barley tea placebo, a very small difference, with no change in fasting glucose, insulin or blood fats. In the dried root bowel trial, fasting glucose, insulin and HOMA-IR did not differ from placebo.
Stool frequency with chicory inulin at 12 g a day (isolated fiber)
This concerns inulin extracted from the root, not the whole root. The EU authorizes the claim that chicory inulin contributes to normal bowel function by increasing stool frequency, at 12 g a day of native chicory inulin. In 44 adults with constipation, 12 g a day gave 4 stools a week versus 3 on placebo. In 12 healthy men, 20 g a day did not change stool weight or transit time.
Traditional herbal tea for mild digestive discomfort
The European Medicines Agency accepts chicory root tea (2 to 4 g of cut root in 250 mL of water once daily) as a traditional herbal medicine for mild digestive complaints such as fullness, flatulence and slow digestion, and for temporary loss of appetite. This rests on long-standing use, not on clinical trials of the tea.
Mechanism of action
Colonic fermentation of root inulin
Inulin from chicory root is not digested in the small intestine and is fermented by colon bacteria. In the dried root trial this raised Bifidobacterium and Anaerostipes and fecal acetate, propionate and butyrate; in lab co-cultures, these bacteria together turned the root product into butyrate.
Fiber kept inside intact plant cells
Dried whole root delivers its inulin still enclosed in cell walls of pectin, cellulose and hemicellulose (about 85% fiber in the tested product). The trial authors propose that this slows fermentation so it continues further along the colon, but this was not measured directly in people.
Bitter sesquiterpene lactones
The root contains sesquiterpene lactones, mainly lactucin, 8-deoxylactucin and lactucopicrin, which give chicory its bitter taste. The EU herbal assessment lists them among the root's constituents; their effects in people taking chicory root have not been established.
Clinical trials
Randomized, investigator-blinded, placebo-controlled parallel trial of bowel function, gut bacteria and glucose markers: dried chicory root cubes (WholeFiber) at 15 g/day for 2 weeks, then 30 g/day for 3 weeks, then 2 weeks off, versus maltodextrin. Publicly funded; the maker supplied the product and one author advised it. (Puhlmann et al. 2022, Gut Microbiome (Camb))
55 adults aged 40 to 75 in the Netherlands with high-normal fasting glucose plus a high diabetes risk score, or raised fasting glucose (28 root, 27 placebo analyzed; 60 enrolled).
The primary outcomes, fasting glucose, insulin and HOMA-IR, did not differ from placebo. Stool softness rose from 3.3 to 4.4 (Bristol scale), differing from placebo over time (p = 0.034), though placebo started softer; stool frequency rose from 1.3 to 1.9 a day within the root group, with placebo near 1.3. Bifidobacterium and Anaerostipes reached about three times placebo levels, and fecal short-chain fatty acids rose 26% in the root group versus a slight fall on placebo (p = 0.023).
Randomized, double-blind, placebo-controlled parallel trial of insulin sensitivity (clamp test), liver fat and gut bacteria: dried chicory root cubes (WholeFiber) at half dose for 2 weeks, then 30 g/day for 10 weeks, versus puffed millet (NCT04714944). Funded by an EFSD/Lilly program and Health Holland; one author is employed by the maker and another sits on its scientific board. (Omary et al. 2025, Cell Rep Med)
42 adults aged 45 to 70 with BMI 28 to 35 and insulin resistance or prediabetes were randomized; 35 were analyzed (17 root, 18 placebo).
The primary outcome, peripheral insulin sensitivity, only trended toward improvement (p = 0.085). Whole-body insulin sensitivity (p = 0.032) and non-oxidative glucose disposal (p = 0.027) rose and triglycerides fell (p = 0.049) versus placebo; liver fat only trended lower (p = 0.063). Body weight and body fat did not change, changes in defecation frequency and consistency were not significant versus placebo, and flatulence rose over time in the root group.
Randomized, double-blind, placebo-controlled trial of blood sugar, blood fat and bowel markers: 300 mL/day of a drink brewed from 10 g of roasted chicory root (0.25 g inulin per 100 mL) versus barley tea with 10% coffee. The root came from a Japanese farm with which one author is affiliated; the authors declared no conflicts. (Nishimura et al. 2015, J Tradit Complement Med)
47 healthy Japanese adults (39 women, 8 men) aged 33 to 70.
HbA1c fell 0.09 percentage points versus 0.03 on placebo (p = 0.018), a very small difference. Fasting glucose, insulin, cholesterol, triglycerides, body weight and blood pressure did not differ between groups. Defecation rhythm scores only trended better (p = 0.051). The drink supplied about 0.75 g of inulin a day, far below the 12 g a day in the EU claim for chicory inulin.
Two randomized, double-blind studies of digestive tolerance of a soluble roasted chicory extract added to coffee drinks: a crossover of 6-day periods (sucrose alone, or extract supplying 5.0 or 7.8 g inulin) and a 4-week parallel study (extract supplying 5.0 g inulin/day versus sucrose). The lead author is from Naturalpha, a French research company; the abstract names no funder. (Ripoll et al. 2010, Nutrition)
Healthy adults: 18 in the crossover study and 35 in the 4-week study.
At 7.8 g inulin in a morning coffee drink, overall abdominal discomfort rose slightly after 1 week (P = 0.05). At 5.0 g inulin a day for 4 weeks, flatulence, bloating, abdominal pain and stool measures did not differ from the sucrose control. At 5 g of inulin a day, digestive symptoms did not differ from the control.
Phase 1, randomized, double-blind, placebo-controlled dose-escalation trial of safety and tolerability (primary) and joint symptoms (secondary) for a proprietary chicory root extract at 600, 1,200 or 1,800 mg/day for 1 month (NCT01010919). Funded by Phytomedics, the extract's developer, which employed two authors. (Olsen et al. 2010, BMC Musculoskelet Disord)
40 adults over 50 with osteoarthritis of the hip or knee, in 3 dose cohorts.
No clinically significant changes in vital signs or routine blood tests were seen. In the top dose cohort, 9 of 10 on the extract and 4 of 8 on placebo had at least 20% improvement in pain, stiffness and global scores (P = 0.06, not significant). One person on 1,800 mg/day stopped because of headache and diarrhea. This was a 1-month safety study, not proof of joint benefit.
Isolated chicory inulin, not whole root. Randomized, double-blind, placebo-controlled crossover trial of bowel function: 3 x 4 g/day Orafti Inulin versus maltodextrin for 4 weeks each, with a 2-week washout (NCT02548247). Two authors were from the BENEO-Institute, part of the inulin maker. (Micka et al. 2017, Int J Food Sci Nutr)
44 otherwise healthy adults with constipation.
Median stool frequency was 4.0 a week on inulin versus 3.0 on placebo (p = 0.038), with softer stools and a trend toward higher satisfaction (p = 0.059). That is about one extra bowel movement a week.
Isolated chicory inulin, not whole root. Randomized, double-blind crossover trial of bowel function: a controlled diet with or without 20 g/day chicory inulin (chain length 2 to 60) in low-fat ice cream, 3 weeks each. (Slavin et al. 2011, Food Funct)
12 healthy men.
Stool weight, transit time, stool frequency and consistency did not change. Total anaerobic bacteria and Lactobacillus rose, and fecal ammonia and beta-glucuronidase activity fell. Flatulence increased significantly with inulin.