The most useful thing to know about the grapevine is that its parts do not do the same job. The leaf has been tested in randomized trials for heavy, swollen legs, and it helped. The seed has small, uneven effects on cholesterol and blood pressure. The fruit is a perfectly good fruit with no special powers. And wine — the part with the most romantic reputation — is the part with the clearest documented harm.
So the real answer to a question about Vitis vinifera health benefits depends entirely on which part of the plant you mean. Below is what the research supports for each one, where it thins out, and who should be careful. If you take prescription medication, treat this as information to discuss with a clinician rather than a reason to start anything.
What Vitis vinifera actually is
Vitis vinifera is the common grapevine: a woody climbing plant in the Vitaceae family behind nearly all table grapes, raisins and wine grapes. It probably originated in southern Europe and western Asia and is now grown across temperate regions worldwide (LiverTox, NIDDK, 2023).
Four parts turn up in health products: the leaves — especially red-pigmented varieties — the seeds, the fruit, and historically the spring sap. The compounds behind the interest are polyphenols. Red vine leaf is rich in flavonoids, chiefly quercetin-3-O-glucuronide and isoquercitrin (Kiesewetter et al., 2000). Grape seed is rich in proanthocyanidins, the same family found in cocoa, tea and many fruits (Memorial Sloan Kettering, 2022).
Red vine leaf: the best-supported Vitis vinifera health benefit
If any part of this plant has earned its reputation, it is the leaf — and specifically a standardized red vine leaf extract coded AS 195, used in Europe for chronic venous insufficiency. That is the condition behind aching, heavy, swollen legs that feel worse after standing and better with the feet up.
In a 12-week randomized, double-blind, placebo-controlled trial of 260 adults with mild to early-moderate venous insufficiency, once-daily doses of 360 mg and 720 mg reduced lower-leg volume measured by water displacement, while the placebo group’s legs got slightly larger. The difference versus placebo at 12 weeks was about 76 g at the lower dose and about 100 g at the higher one, with matching reductions in calf circumference and improvements in patient-rated symptoms (Kiesewetter et al., Arzneimittelforschung, 2000).
A 2020 systematic review pulled together five eligible trials and reached a more measured conclusion: red vine leaf extract improved leg volume, calf and ankle circumference, heaviness, tingling and pain — but only in some of the trials, and the authors called for higher-quality studies before treating the evidence as settled (Azhdari et al., Phytotherapy Research, 2020).
The wider picture agrees. A Cochrane review of phlebotonics — the drug class red vine leaf belongs to — found moderate-certainty evidence that these agents probably reduce leg swelling slightly compared with placebo, and probably reduce ankle circumference by roughly 4 mm. It also found they probably make little or no difference to quality of life, likely do not help venous ulcers heal, and slightly increase side effects (Martinez-Zapata et al., Cochrane Database of Systematic Reviews, 2020).
What that means in practice: this is symptom relief, not repair. Damaged vein valves stay damaged. Expect legs that feel less heavy and swollen, not veins that disappear. If you want to understand the underlying condition first, our guide to what varicose veins are and why they develop covers the mechanism.
Grape seed extract: small and uneven effects on cholesterol and blood pressure
Grape seed extract is the most heavily marketed part of the plant, and the evidence is real but modest — and the sources genuinely disagree on the details.
The US National Center for Complementary and Integrative Health summarizes two pooled analyses: a 2020 review of 11 studies in 536 people found favourable effects on LDL cholesterol and triglycerides but not on total or HDL cholesterol, and a 2022 review of 19 studies in 1,080 people found a reduction in diastolic blood pressure but not systolic (NCCIH, 2025). Memorial Sloan Kettering’s herb database reads the meta-analyses the other way, describing a possible reduction in systolic pressure and heart rate, with mixed findings on lipids, glucose and inflammation (Memorial Sloan Kettering, 2022).
That disagreement is the honest headline. Two respected institutions read overlapping evidence and landed on different numbers, which tells you the effect is small enough that study selection changes the answer.
The size of the effect supports that reading. A meta-analysis summarized by the NIH’s LiverTox database found average changes of roughly 2 mg/dL in fasting glucose, 6 mg/dL in total cholesterol and 6.5 mg/dL in triglycerides, with no change in HbA1c or body weight (LiverTox, NIDDK, 2023). Those are real numbers. They are also small enough that diet does more — see our evidence review of foods that lower blood pressure. Grape seed extract is not approved by the FDA for any medical condition (LiverTox, NIDDK, 2023).
Vitis vinifera health benefits at a glance
| Part of the plant | Claimed use | Strength of evidence | What to realistically expect |
| Red vine leaf extract (AS 195) | Heavy, aching, swollen legs from venous insufficiency | Moderate — several RCTs plus a Cochrane review of the drug class | Less swelling and heaviness over ~12 weeks. Does not repair veins or heal ulcers. |
| Grape seed extract | Cholesterol, blood pressure | Limited and mixed — pooled analyses disagree on which number moves | Small average changes; reviews conflict on systolic vs diastolic effects. |
| Whole grapes | General nutrition | Strong for basic nutrition; no disease-specific claim | A hydrating, potassium-containing fruit. Nothing more, nothing less. |
| Wine | Heart health, “good blood” | Contradicted — alcohol is a Group 1 carcinogen | No safe level established. Not a way to get grape polyphenols. |
| Grape-only “cure” diet | Detox, cleansing, weight loss | None — no controlled human trials | Not advisable; risky in diabetes, kidney disease and pregnancy. |
| Vine sap applied to the eyes | Conjunctivitis, styes, eye hygiene | None — traditional use only | Do not do this. Non-sterile liquid in the eye risks infection. |
Grapes as food: good, ordinary fruit
Strip away the folklore and grapes are a sensible snack. A half-cup serving of seedless grapes supplies about 52 calories, roughly 13.7 g of carbohydrate, 0.7 g of fibre and 2.4 mg of vitamin C (USDA FoodData Central, via California Dept. of Education, 2026). Purple and red varieties carry anthocyanins in the skins, which is where the deep colour comes from.
The reasonable claim is that grapes fit comfortably into a fruit-and-vegetable-rich pattern of eating, which is associated with better cardiovascular health. The unreasonable claim is that grapes treat anaemia, gout, kidney disease or high blood pressure. Grapes are also relatively high in natural sugar for their volume, so if you are managing blood glucose, portion matters more than with lower-sugar fruit.
Why wine is not the medicinal part of the plant
The idea that wine is “good for the heart” has not held up. In January 2023 the World Health Organization published a statement in The Lancet Public Health concluding there is no safe amount of alcohol that does not affect health. Alcohol has been classified as a Group 1 carcinogen by the International Agency for Research on Cancer — the same category as asbestos and tobacco — and causes at least seven types of cancer, including bowel and breast cancer (WHO, 2023).
The detail most people miss is that the harm is not confined to heavy drinking. WHO reports that half of all alcohol-attributable cancers in the European Region come from light and moderate consumption (WHO, 2023). And the apparent protective effect seen in older observational studies is, in WHO’s account, tightly bound up with the comparison groups and statistical methods those studies used.
There is no need to overstate this to make the point. If you want grape polyphenols, wine is a poor delivery system for them, because it comes packaged with a carcinogen. If you drink, that is a personal decision — but it is not a health strategy, and it is not a Vitis vinifera health benefit.
The “grape cure”: a tradition that does not hold up
Older herbal texts recommend eating one to three kilograms of grapes as the only food for three days to a week, described as cleansing or depurative. There are no controlled human trials supporting this, and the underlying premise is wrong: your liver, kidneys and lungs clear waste continuously, and no food takes over that job. Our review of what blood-cleansing herbs actually do goes through the same reasoning in more detail.
There are also practical risks. Several days of nothing but fruit means very little protein, almost no fat and a large, repeated sugar load. That is a genuinely bad idea for anyone with diabetes or impaired glucose control, anyone with chronic kidney disease, anyone who is pregnant or breastfeeding, children, older adults at risk of muscle loss, and anyone with a history of disordered eating. If you want the benefits of eating more fruit, eat more fruit alongside your normal meals.
Traditional uses with little or no evidence
Several practices are still repeated in herbal literature. They are worth knowing about, and worth being clear-eyed about.
- Vine sap in the eyes. Traditionally collected from cut spring shoots and used to wash irritated eyes. Skip this one entirely. Non-sterile plant liquid in the eye is an infection risk, and eye symptoms need proper assessment.
- Dried leaf powder inhaled for nosebleeds. No supporting evidence. Recurrent nosebleeds deserve a medical opinion rather than a home remedy.
- Leaf decoction sitz baths and footbaths. Comfortable and low-risk, but the comfort probably comes from the warm water and the leg elevation rather than the leaves. Warm sitz baths are a standard piece of hemorrhoid self-care in their own right. If you are exploring plant options for that, our overview of herbs used for hemorrhoids covers the wider set.
- Leaf tea for heavy periods or diarrhoea. This comes from the tannin content and traditional use, not from clinical trials. Heavy menstrual bleeding and persistent diarrhoea both have causes worth diagnosing.
Safety: side effects, interactions, and who should be careful
Side effects
Grape leaf and seed extracts are generally well tolerated. In clinical trials, reported adverse events included mild itchy skin, dizziness, headache and nausea — often at a similar rate to placebo (LiverTox, NIDDK, 2023). Memorial Sloan Kettering lists gastrointestinal upset (Memorial Sloan Kettering, 2022). A safety study giving healthy adults 1,000 to 2,500 mg of grape seed extract daily for four weeks reported occasional headache, nausea, constipation and diarrhoea with no change in liver blood tests (LiverTox, NIDDK, 2023). Liver injury from grape extracts has not been reported (LiverTox, NIDDK, 2023).
Medication interactions
This is the part to take seriously, and the evidence here is mostly laboratory-level rather than clinical.
- Anticoagulants and antiplatelets. Grape seed shows antiplatelet activity in laboratory testing and may add to the effect of these drugs; MSK advises talking to your provider if you take warfarin, noting a possible increase in bleeding risk. Clinical relevance has not been established (Memorial Sloan Kettering, 2022).
- Drugs metabolized by CYP3A4 or UGT enzymes. Grape seed extract inhibits CYP3A4 and modulates UGT enzymes in vitro, which could in principle alter levels of a wide range of medications. Again, clinical relevance is undetermined (Memorial Sloan Kettering, 2022).
- Anything else you take daily. NCCIH’s general advice applies: if you take any medicine, speak to your provider before adding grape seed extract, because some herbs and medicines interact in harmful ways (NCCIH, 2025).
Pregnancy and breastfeeding
Little is known about whether grape seed extract is safe during pregnancy or while breastfeeding (NCCIH, 2025). That is an absence of data rather than proof of harm, but it is a good reason not to use concentrated extracts in either situation without your obstetric provider’s agreement. Eating grapes as food is a different matter and is not a concern.
Who should avoid grapevine supplements
- Anyone taking warfarin, apixaban, rivaroxaban, clopidogrel or daily aspirin, unless a clinician has cleared it.
- Anyone with a bleeding disorder, or with surgery or a dental procedure coming up — tell your surgical team about every supplement you take.
- People who are pregnant or breastfeeding.
- Children, who have not been studied.
- People undergoing chemotherapy or radiotherapy, who should raise any antioxidant supplement with their oncology team before starting.
One labelling trap worth knowing: grape seed extract is not the same thing as grapefruit seed extract, despite both being abbreviated GSE. They have different biological effects (Memorial Sloan Kettering, 2022).
When to see a doctor
Leg and rectal symptoms are exactly the situations where a plant remedy can quietly delay a diagnosis that matters. Use these as your thresholds.
Book a routine appointment if:
- you have varicose veins with pain, itching or swelling, or a sore on your leg that has not healed after two weeks (NHS, 2024);
- hemorrhoid symptoms persist after a week of home treatment (NIDDK, 2016);
- leg swelling is new, one-sided, or does not settle overnight.
Seek urgent or same-day care if:
- a varicose vein bleeds (NHS, 2024);
- you have any bleeding from the rectum. Bright red blood is common with internal hemorrhoids, but it can also signal Crohn’s disease, ulcerative colitis or cancer of the colon or rectum, so it needs assessing rather than treating at home (NIDDK, 2016);
- one leg becomes swollen, hot, red or painful — a possible deep vein thrombosis, which is a recognized complication of varicose veins and needs immediate attention.
- you have chest pain or sudden breathlessness. In the US, call 911.
| Please read this before acting on anything above: This article is general education, not medical advice, and it is not a substitute for diagnosis, treatment or guidance from a qualified healthcare professional. Herbal extracts can interact with prescription medication and are not suitable for everyone. Do not start, stop or change any medicine, supplement or diet on the strength of this page alone. If you are pregnant or breastfeeding, take a blood thinner or any daily medication, have a bleeding or clotting condition, liver or kidney disease or diabetes, or have surgery coming up, speak with your doctor or pharmacist first. If you have symptoms that worry you, get them checked rather than self-treating. If you think you are having a medical emergency, call your local emergency number right away. |
Frequently Asked Questions
Does grape leaf extract get rid of varicose veins?
No. Trials show reduced leg swelling and improved symptoms such as heaviness and tingling over about 12 weeks (Kiesewetter et al., 2000), but nothing in that research shows veins shrinking away. The NHS reserves procedures such as endothermal ablation and foam sclerotherapy for veins that need removing (NHS, 2024).
How long does red vine leaf extract take to work?
In the main trial, symptom improvements separated from placebo between weeks 6 and 12, with the clearest benefit at the 12-week mark (Kiesewetter et al., 2000). If nothing has changed after three months, it is reasonable to stop and talk to a clinician about other options.
Is grape seed extract good for cholesterol?
The effect appears real but small, and the reviews do not fully agree. NCCIH describes favourable effects on LDL and triglycerides but not total or HDL cholesterol (NCCIH, 2025), while a meta-analysis summarized by LiverTox found average reductions of around 6 mg/dL in total cholesterol (LiverTox, NIDDK, 2023). It is not a replacement for a statin or for dietary change.
Is a glass of red wine a day still considered healthy?
Not by the WHO, which states that no level of alcohol consumption is safe for health and that risk begins with the first drink (WHO, 2023). Some researchers continue to argue that the evidence on light drinking is weaker than that framing suggests, so this remains contested — but the direction of official guidance in recent years has been consistently toward drinking less.
Can I just eat grapes instead of taking an extract?
For general nutrition, yes — grapes are a good fruit. But the trials used standardized leaf and seed extracts at specific doses, and you cannot reach those concentrations by eating table grapes. Whole fruit and concentrated extract are different interventions with different evidence behind them.
Is grape seed extract safe to take long-term?
Most safety data cover short study periods — the largest tolerability study ran four weeks (LiverTox, NIDDK, 2023), and the Cochrane review of this drug class noted that only short-term safety data were available, so medium- and long-term safety could not be estimated (Martinez-Zapata et al., 2020). Long-term use is genuinely unstudied territory.
References
- Kiesewetter H, Koscielny J, Kalus U, et al. “Efficacy of orally administered extract of red vine leaf AS 195 (folia vitis viniferae) in chronic venous insufficiency (stages I–II). A randomized, double-blind, placebo-controlled trial.” Arzneimittel-Forschung, 2000;50(2):109–117. PMID 10719612. → View source
- Azhdari M, Zilaee M, Karandish M, et al. “Red vine leaf extract (AS 195) can improve some signs and symptoms of chronic venous insufficiency, a systematic review.” Phytotherapy Research, 2020;34(10):2577–2585. PMID 32314844. → View source
- Martinez-Zapata MJ, Vernooij RWM, Simancas-Racines D, et al. “Phlebotonics for venous insufficiency.” Cochrane Database of Systematic Reviews, 2020, Issue 11, Art. No. CD003229.pub4. → View source
- National Center for Complementary and Integrative Health. “Grape Seed Extract: Usefulness and Safety.” NCCIH, National Institutes of Health, last updated February 2025. → View source
- Memorial Sloan Kettering Cancer Center. “Grape Seed — Purported Benefits, Side Effects & More.” Integrative Medicine, About Herbs database, last updated 10 February 2022. → View source
- “Grape Seed.” In: LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. National Institute of Diabetes and Digestive and Kidney Diseases, updated 20 March 2023. Bookshelf ID NBK590485. → View source
- World Health Organization Regional Office for Europe. “No level of alcohol consumption is safe for our health.” News release, 4 January 2023. → View source
- NHS. “Varicose veins.” NHS website, page last reviewed 1 July 2024. → View source
- National Institute of Diabetes and Digestive and Kidney Diseases. “Symptoms & Causes of Hemorrhoids.” NIDDK, last reviewed October 2016. → View source
- U.S. Department of Agriculture, FoodData Central, via California Department of Education Food Distribution fact sheet, “Grapes, Variety,” last reviewed 10 July 2026. → View source
