Oat Straw

Metadata

Approved Indications

Commission E (Germany)

• Approved (external use only): Baths for inflammatory and seborrheic skin conditions, including itching
• Not approved for internal nervous system use: Commission E did not grant approval for the nervine/sedative indication despite widespread traditional use. This is a notable gap between regulatory approval and folk tradition.

ESCOP

• No monograph: ESCOP has not published a monograph on Avena sativa herba or stramentum. This absence reflects the limited clinical evidence available to support formal monograph development.

EMA/HMPC

• Traditional use (internal — Avenae herba): Relief of mild symptoms of mental stress and to aid sleep. Adopted September 2008. These conclusions cover preparations obtained by comminuting the aerial parts, expressing juice from the fresh herb, or preparing liquid/dry extracts with solvents (ethanol or water). For adults and adolescents over 12 years only.
• Traditional use (external — Avenae stramentum): As a bath additive for minor skin complaints including itching and oily/seborrheic skin.
• Note: The HMPC also issued a separate monograph on Avenae fructus (oat grain/fruit) for minor skin inflammation and wound healing.

Agreement/Disagreement

Commission E and EMA agree on the external bath indication for skin conditions. However, they diverge on nervous system use: Commission E did not approve oral nervine use, while the EMA grants traditional use status for mild mental stress. Neither body classifies oat straw under “well-established use,” and ESCOP’s absence of a monograph further underscores the limited regulatory confidence. The gap between strong folk tradition (oat straw as a premier nervine tonic) and weak regulatory/clinical support is one of the defining features of this herb’s profile.

Conditions Treated

Primary (Traditional Use)

• Mild nervous tension and stress — Oat straw is traditionally regarded as a gentle nervine tonic, used for states of nervous exhaustion, mild anxiety, and tension. The EMA grants traditional use status for this indication. It is considered a “trophorestorative” in Western herbal medicine, meaning it is thought to nourish and restore depleted nervous tissue over time rather than providing immediate sedation.
• Sleep support — Included in the EMA traditional use indication. Oat straw is typically used as a gentle aid to promote restful sleep rather than as a primary sedative herb.

Secondary (Limited/Emerging Evidence)

• Cognitive function in healthy adults — A proprietary green oat extract (Neuravena/EFLA 955) has shown modest improvements in attention, processing speed, working memory, and executive function in several small RCTs. This is the most clinically investigated application, though evidence remains preliminary and is tied to a single proprietary extract.
• Cerebrovascular health — Chronic supplementation with Neuravena improved brachial flow-mediated dilatation and cerebrovascular responsiveness in one small crossover trial in older adults.

Traditional/Historical

• Nervine tonic and trophorestorative — In European and Anglo-American folk herbalism, oat straw (and especially milky oats harvested at the immature “milky” grain stage) is one of the most widely recommended nervous system restoratives. Herbalists use it for nervous debility, convalescence, and chronic stress states.
• Opium and tobacco withdrawal (historical) — In the 1960s-1970s, an Ayurvedic practitioner (C.L. Anand) reported success treating opium addiction with oat tincture and published a report in Nature (1971) claiming that an alcoholic extract of Avena sativa reduced cigarette smoking. A small case series reported 6 of 10 opium addicts successfully ceased use after 27-45 days of treatment with a green oat decoction. However, a subsequent controlled study (Connor, 1975) failed to replicate the smoking cessation findings, and this application is now considered unsubstantiated.
• Skin conditions (external bath) — Approved by Commission E for inflammatory and seborrheic skin conditions. Colloidal oatmeal baths have a long history for soothing itchy, irritated skin and are widely used in dermatology.
• Nutritive tonic — Oat straw is rich in minerals (calcium, iron, silica, manganese, zinc) and has traditionally been used as a nutritive herb for bone health and connective tissue support, though clinical evidence for these claims is absent.

Mechanism of Action

The pharmacology of oat straw and green oat extracts is incompletely understood. Several proposed mechanisms have been identified primarily through in vitro and animal research, with limited clinical pharmacological investigation.

MAO-B Inhibition

A wild green oat extract (Neuravena) has demonstrated significant inhibitory activity against monoamine oxidase B (MAO-B) in vitro. MAO-B is the enzyme primarily responsible for metabolizing dopamine in the brain. Inhibition of MAO-B would be expected to increase dopaminergic neurotransmission, which could plausibly account for improved working memory and executive function. This mechanism was identified during bioactivity-guided fractionation of the extract and is considered the leading candidate mechanism for the cognitive effects observed in clinical trials. [Source: Dimpfel et al. 2011; Kennedy et al. 2017]

PDE4 Inhibition

The same extract has shown inhibitory effects on phosphodiesterase type 4 (PDE4), an enzyme that degrades cyclic adenosine monophosphate (cAMP), a key intracellular second messenger. PDE4 inhibition prolongs cAMP signaling, which is associated with enhanced long-term memory formation, wakefulness, anti-inflammatory effects, and antidepressant-like activity. Pharmaceutical PDE4 inhibitors (e.g., roflumilast) are used clinically for inflammatory conditions, and the cognitive-enhancing potential of PDE4 inhibition is an active area of neuroscience research. [Source: Kennedy et al. 2017; Frontiers in Neuroscience 2021]

Avenanthramide Anti-inflammatory Pathways

Avenanthramides — polyphenolic amides unique to oats — exhibit potent anti-inflammatory and antioxidant activity. Avenanthramide-C in particular has been shown to inhibit NF-kB activation, preventing nuclear translocation and downstream expression of inflammatory cytokines (TNF-alpha, IL-6, IL-1beta). Avenanthramides also enhance nitric oxide (NO) production in human aortic smooth muscle cells, which may contribute to the vasodilatory effects observed in clinical studies. Their antioxidant activity involves direct hydrogen atom donation to free radicals. In the skin, avenanthramides exert antihistaminic and anti-itch effects, providing the pharmacological basis for the long-standing use of oat baths for pruritus. [Source: Meydani 2009; Sur et al. 2008; PMC6126071]

Potential GABA Modulation

Some sources propose GABAergic modulation as a mechanism underlying the traditional nervine/sedative reputation of oat straw. Vitexin and isovitexin, flavonoids present in oat herb, are structurally similar to flavonoids found in other GABAergic herbs (e.g., passionflower). However, direct evidence for clinically relevant GABA receptor activity from oat straw preparations is lacking. [UNCERTAIN — proposed mechanism without strong supporting data]

Cerebrovascular Effects

Chronic supplementation with green oat extract improved both peripheral (brachial artery) and cerebral vasodilator function in one clinical trial. Enhanced cerebrovascular responsiveness could increase cerebral blood flow under cognitive demand, potentially contributing to the cognitive benefits observed in other trials. The mechanism may involve avenanthramide-mediated NO enhancement and anti-inflammatory effects on the vascular endothelium. [Source: Wong et al. 2013]

Summary of Mechanistic Understanding

The mechanistic evidence is most developed for the proprietary Neuravena extract rather than for traditional oat straw tea or tincture preparations. Whether traditional preparations achieve sufficient concentrations of the relevant bioactives (particularly to inhibit MAO-B and PDE4) is unknown. The folk tradition of oat straw as a nervine tonic may reflect different mechanisms (nutritive mineral content, mild GABA effects) than those identified in the Neuravena research (MAO-B and PDE4 inhibition).

Clinical Evidence Summary

Overview

The clinical evidence for oat straw is limited and almost entirely confined to studies on a proprietary green oat extract (Neuravena/EFLA 955, manufactured by Frutarom, now part of IFF). There are no large-scale clinical trials on traditional oat straw tea or tincture for nervous system indications. The available RCTs are small (n = 17-132), and most examine acute (single-dose) rather than chronic effects.

Berry et al. (2011) — Stroop Test (Acute, Elderly)

• Design: Double-blind, randomized, placebo-controlled crossover
• n = 37 elderly volunteers with below-average cognitive performance
• Intervention: Single doses of 0, 1600, and 2400 mg Neuravena at weekly intervals
• Result: Significantly fewer errors on the color-naming component of the Stroop Color-Word Test after the 1600 mg dose compared to placebo and 2400 mg. No significant effect at 2400 mg.
• Key finding: Suggests an inverted U-shaped dose-response, with 1600 mg outperforming a higher dose
• Limitation: Very small sample; single cognitive test; acute dosing only
• [Source: J Altern Complement Med. 2011;17(7):635-637. PubMed 21711204]

Dimpfel et al. (2011) — EEG Study (Acute)

• Design: Double-blind, randomized, placebo-controlled crossover
• n = 36 healthy subjects
• Intervention: Single doses of 1250 or 2500 mg Neuravena vs. placebo
• Measurements: Quantitative EEG (CATEEM brain mapping) during rest and cognitive tasks (d2-concentration test, mental arithmetic)
• Result: Significant changes in EEG spectral frequencies in the left frontotemporal area, including lowering of spectral delta power during rest and enhancement of spectral theta power during concentration tasks. No effect detected using P300 paradigm.
• Key finding: Provides neurophysiological evidence that ingested oat extract reaches and modulates brain activity
• Limitation: Surrogate electrophysiological endpoint, not a direct measure of cognitive improvement
• [Source: J Altern Complement Med. 2011;17(5):427-434. PubMed 21563962]

Wong et al. (2012) — Chronic Cognitive Effects in Older Adults

• Design: Randomized, double-blind, placebo-controlled crossover
• n = 37 healthy adults aged 67 +/- 0.8 years
• Intervention: 1500 mg/day Neuravena vs. placebo for 12 weeks per arm
• Result: An acute cognitive benefit was observed, but chronic supplementation over 12 weeks did not produce sustained cognitive improvement on the battery of tests used
• Limitation: Small sample size; cognitive tests may not have been sensitive enough to detect subtle chronic changes
• [Source: Nutr J. 2012;11:33. PubMed 22690320]

Wong et al. (2013) — Cerebrovascular Function in Older Adults

• Design: Randomized, double-blind, placebo-controlled crossover (same cohort as cognitive study)
• n = 37 healthy adults aged 67 +/- 0.8 years
• Intervention: 1500 mg/day Neuravena vs. placebo for 12 weeks per arm
• Result: Significant improvements in brachial flow-mediated dilatation (FMD) and cerebrovascular responsiveness to hypercapnia (increases of approximately 41-42%)
• Key finding: Demonstrates that chronic oat extract supplementation improves vascular function in both systemic and cerebral arteries, suggesting cardiovascular health benefits
• Limitation: Small sample; surrogate vascular endpoints rather than hard clinical outcomes
• [Source: J Hypertens. 2013;31(1):167-176. PubMed 23221935]

Kennedy et al. (2017) — Acute Cognitive Effects in Middle-Aged Adults

• Design: Double-blind, placebo-controlled, counterbalanced crossover
• n = 42 healthy adults aged 40-65 who self-reported memory decline
• Intervention: Single doses of placebo, 800 mg, or 1600 mg Neuravena on six occasions (each treatment repeated twice)
• Result: 800 mg dose increased global speed of performance across all timed tasks, improved delayed word recall accuracy, enhanced executive function (Peg and Ball task — decreased thinking time and completion time), and increased working memory span (Corsi blocks, on second administration only). The 1600 mg dose showed fewer significant effects.
• Key finding: Optimal cognitive dose appears to be 800 mg or below, confirming an inverted U-shaped dose-response curve
• Limitation: Acute dosing only; repeated within-subject design helps but sample remains modest
• [Source: Nutr Neurosci. 2017;20(2):135-151. PubMed 26618715]

Kennedy et al. (2020) — Acute and Chronic Effects with Stressor (cognitaven)

• Design: Randomized, double-blind, placebo-controlled
• n = 132 healthy adults aged 35-65
• Intervention: 430 mg, 860 mg, or 1290 mg of a green oat extract (cognitaven) vs. placebo for 29 days
• Result: Confirmed acute cognitive benefits (improvements on Corsi blocks, dual-task multitasking). Chronic supplementation benefited cognitive function. The highest dose (1290 mg) lowered the physiological response to a laboratory stressor. Mood ratings did not show robust changes.
• Key finding: First demonstration that chronic supplementation (not just acute) can benefit cognitive function; stress-reactivity reduction at highest dose
• Limitation: Proprietary extract (cognitaven, not Neuravena); modest effect sizes
• [Source: Nutrients. 2020;12(6):1598. PMC7352613]

Sadowska-Krowicka et al. (2021) — Neurophysiological Correlates

• Design: Randomized, double-blind, placebo-controlled
• n = 40 healthy adults
• Intervention: Single dose of 800 mg Neuravena vs. placebo
• Measurements: Cognitive performance tasks plus quantitative EEG (qEEG)
• Result: Positive effects on executive function, processing speed, and attention, with corresponding changes in EEG activity
• Key finding: Provides neurophysiological correlates supporting the cognitive effects at the 800 mg dose
• [Source: Front Neurosci. 2021;15:748188. PMC8517335]

Historical: Anand (1971) — Smoking Cessation

• Design: Open-label case report / small uncontrolled trial
• Intervention: Alcoholic extract of Avena sativa administered to cigarette smokers
• Result: Reported reduction in cigarette craving and consumption
• Follow-up (Connor 1975): A controlled study failed to replicate the smoking cessation findings
• Status: This application is considered unsubstantiated
• [Source: Nature. 1971;233(5320):496. PubMed 4939551; Nature. 1975;252:580]

Overall Assessment

The cognitive evidence is promising but preliminary. All positive trials used proprietary standardized extracts (Neuravena or cognitaven), and the findings cannot be directly extrapolated to traditional oat straw preparations (tea, tincture, infusion). The evidence for the traditional nervine/stress-relief indication relies almost entirely on long-standing use rather than clinical trials. No RCTs have evaluated traditional oat straw tea or tincture for anxiety, nervous tension, or sleep.

European vs. US/Anglophone Consensus

Safety Profile

General Assessment

Oat straw and green oat preparations have an excellent safety record. Oats are among the most widely consumed grains globally, and the aerial parts share this favorable safety profile. No significant adverse effects have been reported in clinical trials or in decades of traditional use.

Contraindications

• Known hypersensitivity to oats or other grasses in the Poaceae family
• Celiac disease / gluten sensitivity: Oats do not contain wheat gluten proteins (gliadin) but do contain avenin, a related prolamin. Most individuals with celiac disease tolerate pure oats well. However, commercial oat products are frequently contaminated with wheat, barley, or rye. Individuals with celiac disease should use certified gluten-free oat straw products if consuming this herb. The EMA does not list celiac disease as a contraindication for oat herb preparations.
• Intestinal obstruction: People with disorders of the esophagus, stomach, or intestines that could prolong transit time should use caution with oat fiber products (more relevant to oat bran than to oat straw herb)
• EMA: Not recommended for children under 12 years (due to lack of safety data, not due to known harm)

Drug Interactions

• No significant drug interactions documented in clinical use with oat straw preparations
• Oat bran (not oat straw): Oat bran fiber may theoretically decrease absorption of some medications if taken simultaneously (reported with HMG-CoA reductase inhibitors and iron supplements). This concern relates to the fiber content of oat grain products, not to oat straw herb preparations.
• Theoretical: Given the in vitro MAO-B inhibitory activity, some caution might theoretically be warranted with MAO inhibitor medications, but no clinical interactions have been reported and the degree of MAO-B inhibition from oral preparations is unlikely to be clinically significant [UNCERTAIN]

Side Effects

• Extremely rare at recommended doses
• At the time of the EMA/HMPC assessment, no side effects had been reported
• Clinical trials with Neuravena extract (doses up to 2500 mg) reported no significant adverse events
• Allergic reactions: Possible in individuals with grass pollen allergy (Poaceae family cross-reactivity), though rare with oral preparations
• GI discomfort: Mild and infrequent

Pregnancy and Lactation

• Pregnancy: Not recommended due to insufficient safety data. No evidence of harm, but formal safety studies have not been conducted.
• Lactation: Not recommended due to insufficient data. Oats as food are consumed freely during lactation without concern; the safety of concentrated herbal extracts is less established.

Clinical Dosage

Traditional Oat Straw Preparations

Herbal Tea (Infusion)

• Dried oat straw (Avenae stramentum): 3-5 g of cut herb per 250 mL boiling water, steeped 10-15 minutes. Drink 2-3 cups daily.
• Dried oat herb (Avenae herba): Similar preparation; some herbalists recommend longer steeping (up to 4 hours or overnight as a “nourishing infusion”) to extract minerals

Tincture

• Fresh milky oat tincture (1:2-1:3, 40-50% ethanol): 3-5 mL, three times daily. Traditionally, milky oat tincture is prepared from fresh, undried herb harvested at the milky stage and is considered pharmacologically distinct from dried oat straw.
• Dried oat straw tincture (1:5, 25-45% ethanol): 3-5 mL, three times daily

Bath (External)

• Commission E / EMA: Approximately 100 g of dried oat straw boiled in 3 liters of water for 20-30 minutes, strained, and added to a full bath. Alternatively, commercially prepared colloidal oatmeal bath products.

Proprietary Extracts (Clinical Trial Doses)

• Neuravena (EFLA 955): 800-1600 mg per day. The 800 mg dose appears optimal for acute cognitive effects based on Kennedy et al. (2017). The 1500 mg/day dose was used in the 12-week chronic vascular study (Wong et al. 2013).
• cognitaven: 430-1290 mg per day (Kennedy et al. 2020)

Duration

• EMA: If symptoms persist after 2 weeks of use, consult a healthcare professional
• Traditional herbalism: Oat straw is often recommended for long-term use (weeks to months) as a nervous system trophorestorative, in contrast to fast-acting anxiolytics

Sources

• EMA/HMPC Community Herbal Monograph on Avena sativa L., herba (EMA/HMPC/202966/2007). Adopted September 2008.
• EMA/HMPC Assessment Report on Avena sativa L., herba and Avena sativa L., fructus.
• German Commission E Monograph: Avenae stramentum (Oat straw). Expanded Commission E via HerbalGram.
• Berry NM, Robinson MJ, Bryan J, Buckley JD, Murphy KJ, Howe PRC. Acute Effects of an Avena sativa Herb Extract on Responses to the Stroop Color-Word Test. J Altern Complement Med. 2011;17(7):635-637. PubMed 21711204.
• Dimpfel W, Storni C, Verbruggen M. Ingested oat herb extract (Avena sativa) changes EEG spectral frequencies in healthy subjects. J Altern Complement Med. 2011;17(5):427-434. PubMed 21563962.
• Wong RHX, Howe PRC, Coates AM, Buckley JD, Berry NM. Chronic effects of a wild green oat extract supplementation on cognitive performance in older adults: a randomised, double-blind, placebo-controlled, crossover trial. Nutr J. 2012;11:33. PubMed 22690320.
• Wong RHX, Howe PRC, Buckley JD, Coates AM, Kunz I, Berry NM. Chronic consumption of a wild green oat extract (Neuravena) improves brachial flow-mediated dilatation and cerebrovascular responsiveness in older adults. J Hypertens. 2013;31(1):167-176. PubMed 23221935.
• Kennedy DO, Jackson PA, Forster J, Khan J, Grothe T, Perrinjaquet-Moccetti T, Haskell-Ramsay CF. Acute effects of a wild green-oat (Avena sativa) extract on cognitive function in middle-aged adults: A double-blind, placebo-controlled, within-subjects trial. Nutr Neurosci. 2017;20(2):135-151. PubMed 26618715.
• Kennedy DO, Bonnlander B, Lang SC, Pischel I, Forster J, Khan J, Jackson PA, Grothe T. Acute and Chronic Effects of Green Oat (Avena sativa) Extract on Cognitive Function and Mood during a Laboratory Stressor in Healthy Adults: A Randomised, Double-Blind, Placebo-Controlled Study in Healthy Humans. Nutrients. 2020;12(6):1598. PMC7352613.
• Sadowska-Krowicka E, Bobkiewicz-Kozlowska T, Dimpfel W. Effects of a Green Oat Herb Extract on Cognitive Performance and Neurophysiological Activity: A Randomized Double-Blind Placebo-Controlled Study. Front Neurosci. 2021;15:748188. PMC8517335.
• Anand CL. Effect of Avena sativa on Cigarette Smoking. Nature. 1971;233(5320):496. PubMed 4939551.
• Connor J, Connor T, Marshall PB, Reid A, Turnbull MJ. Lack of effect of Avena sativa on cigarette smoking. Nature. 1975;252:580.
• Meydani M. Potential health benefits of avenanthramides of oats. Nutr Rev. 2009;67(12):731-735.
• Sur R, Nigam A, Bhattacharjee S, Bhargava KP. Avenanthramides, polyphenols from oats, exhibit anti-inflammatory and anti-itch activity. Arch Dermatol Res. 2008;300(10):569-574.
• Singh R, De S, Belkheir A. Avena sativa (Oat), a potential nutraceutical and therapeutic agent: an overview. Crit Rev Food Sci Nutr. 2013;53(2):126-144. PubMed 23072529.
• Lv N, Song J, Wang Y, et al. Avenanthramides, Distinctive Hydroxycinnamoyl Conjugates of Oat, Avena sativa L.: An Update on the Biosynthesis, Chemistry, and Bioactivities. Plants. 2023;12(6):1388. PMC10055937.
• Pereira-Caro G, Borges G, van der Hooft J, et al. Avenanthramides in Oats: Biological Activities, Health Benefits, and Therapeutic Properties. Nutrients. 2018;10(9):1218. PMC6126071.
• CIR Safety Assessment of Avena sativa (Oat)-Derived Ingredients as Used in Cosmetics. Int J Toxicol. 2019.
• Bioactivity-based development of a wild green oat (Avena sativa) extract in support of cognitive function. Planta Med. 2006;72:1006. (Abstract; bioactivity-guided fractionation identifying MAO-B and PDE4 inhibitory activity.)

Connections

• Nervine tonics for stress: compare with Lemon Balm (stronger evidence for anxiety) and Passionflower (better regulatory consensus for nervousness)
• Sleep herbs: compare with Valerian (much stronger clinical evidence), Hops (similar D-rated evidence but different mechanism), Lavender (Silexan has strong evidence for anxiety)
• Cognitive herbs: for evidence-based cognitive support, compare with Bacopa (well-established memory enhancement) and Ginkgo (well-established use for cognitive decline)
• Flavonoid overlap: Oat straw shares vitexin and isovitexin with Passionflower, potentially contributing to similar GABAergic effects
• External/dermatological use: for anti-inflammatory skin applications, compare with Chamomile and Calendula