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The foods high in quercetin in USDA data are capers, fresh dill and cilantro, hot yellow wax peppers, red onions, radicchio, watercress, kale, okra and several berries. USDA SR Legacy, the database we use for most food guides, has no values for this flavonol, so this list uses the USDA Database for the Flavonoid Content of Selected Foods, Release 3.3, exactly as published. USDA reports wide ranges for almost every food, so read each figure as an average of published analyses, not a fixed amount.
Peptide Labs does not sell foods. This article is general nutrition information, not medical advice.
Key Takeaways
- In the USDA flavonoid database, raw capers have the highest average quercetin of any food, about 234 milligrams per 100 grams, followed by canned capers.
- Among everyday vegetables in the USDA table, raw red onions average about 39 milligrams per 100 grams, roughly twice the figure for raw onions overall.
- USDA SR Legacy defines a quercetin field but holds no values for it, which is why this list uses the separate USDA flavonoid database.
- USDA states that considerable variation was observed in the flavonoid content of specific foods; red onion samples alone ranged from about 6 to 192 milligrams per 100 grams.
- USDA cautions against reading raw and cooked values as a cooking effect, because the figures often come from different studies.
Foods high in quercetin: USDA values per 100 grams
The table lists foods from USDA’s Release 3.3 flavonoid table by average quercetin, in milligrams per 100 grams of the edible portion, with the number of samples behind each average and the lowest and highest values USDA recorded. The numbers in parentheses are USDA’s NDB food numbers; USDA assigns temporary numbers starting with 99 to foods that are not in its Standard Reference database. The confidence code is USDA’s own quality grade, explained further down.
| Food (USDA NDB No.) | Quercetin (mg/100 g) | Samples | Range (mg/100 g) | USDA confidence code |
|---|---|---|---|---|
| Capers, raw (99360) | 233.84 | 3 | 149.31 to 323.38 | C |
| Capers, canned (02054) | 172.55 | 20 | 45.05 to 519.85 | B |
| Dill weed, fresh (02045) | 55.15 | 3 | 7.45 to 110.00 | C |
| Coriander (cilantro) leaves, raw (11165) | 52.90 | 4 | 5.00 to 68.86 | C |
| Peppers, hot, yellow wax, raw (99042) | 50.63 | 3 | 28.83 to 78.38 | C |
| Onions, red, raw (99055) | 39.21 | 147 | 5.90 to 191.70 | B |
| Radicchio, raw (11952) | 31.51 | 6 | 9.06 to 52.73 | C |
| Watercress, raw (11591) | 29.99 | 8 | 4.00 to 67.58 | B |
| Elderberries, raw (09088) | 26.77 | 93 | 8.47 to 60.00 | B |
| Onions, cooked, boiled (11283) | 24.36 | 32 | 19.87 to 31.00 | B |
| Kale, raw (11233) | 22.58 | 18 | 0.00 to 56.20 | B |
| Okra, raw (11278) | 20.97 | 12 | 11.10 to 33.22 | B |
| Onions, raw (11282) | 20.30 | 400 | 1.50 to 90.75 | A |
| Apple, skin only (99002) | 19.36 | 8 | 14.76 to 23.49 | C |
| Chia seeds, raw (99602) | 18.42 | 3 | 15.10 to 21.44 | C |
| Cranberries, raw (09078) | 16.64 | 26 | 7.30 to 27.57 | B |
| Buckwheat (20008) | 15.38 | 24 | 5.10 to 36.29 | C |
| Asparagus, cooked, boiled (11012) | 15.16 | 8 | 7.61 to 28.40 | B |
| Onions, sweet, raw (11294) | 14.52 | 28 | 0.97 to 46.32 | B |
| Asparagus, raw (11011) | 13.98 | 36 | 0.05 to 28.72 | B |
| Lingonberries, raw (99021) | 13.30 | 12 | 7.36 to 21.00 | B |
| Onions, spring or scallions (11291) | 10.68 | 4 | 0.00 to 18.00 | B |
| Cocoa, dry powder, unsweetened (19165) | 10.00 | 11 | 8.99 to 20.13 | B |
| Blueberries, cultivated (09050) | 7.67 | 72 | 0.00 to 18.72 | B |
| Lettuce, red leaf, raw (11257) | 7.61 | 29 | 0.45 to 44.90 | B |
Capers and fresh herbs are used by the spoonful, so a 100-gram comparison flatters them; onions, kale, okra and asparagus are eaten in far larger portions. Our guides cover many of these foods in detail: onions, radicchio, watercress, kale, okra, asparagus, buckwheat, dill and cilantro. Our elderberries guide explains why that berry is cooked before it is eaten.
Common foods lower on the list
Several foods that are often named as sources sit much lower in the USDA table. They are eaten often and in larger amounts, but the USDA averages per 100 grams are modest.
| Food (USDA NDB No.) | Quercetin (mg/100 g) | Samples | Range (mg/100 g) | USDA confidence code |
|---|---|---|---|---|
| Apples, raw, with skin (09003) | 4.01 | 139 | 0.00 to 11.47 | B |
| Spinach, raw (11457) | 3.97 | 12 | 0.00 to 27.22 | B |
| Broccoli, raw (11090) | 3.26 | 116 | 0.00 to 13.70 | B |
| Tomatoes, cherry, raw (99011) | 2.76 | 91 | 0.17 to 20.30 | B |
| Cherries, sweet, raw (09070) | 2.29 | 80 | 0.10 to 6.78 | B |
| Lettuce, cos or romaine, raw (11251) | 2.20 | 23 | 0.06 to 8.78 | B |
| Tea, black, brewed (14355) | 2.19 | 64 | 0.89 to 4.75 | B |
| Broccoli, cooked, boiled (11091) | 1.33 | 35 | 0.00 to 3.28 | B |
| Strawberries, raw (09316) | 1.11 | 118 | 0.00 to 4.40 | B |
| Apples, raw, without skin (09004) | 1.05 | 39 | 0.00 to 2.00 | B |
| Tomatoes, red, ripe, raw (11529) | 0.58 | 96 | 0.00 to 3.80 | B |
| Bananas, raw (09040) | 0.06 | 11 | 0.00 to 0.32 | B |
Two patterns stand out in the USDA figures. Apple skin alone averages 19.36 milligrams per 100 grams, whole apples with skin 4.01 and peeled apples 1.05, so in USDA data most of an apple’s quercetin sits in the peel. Cherry tomatoes average more than standard red tomatoes in the USDA table. For brewed tea, USDA standardized every value to a 1% infusion, meaning 1 gram of leaves per 100 milliliters of boiling water. See our guides to apples, tomatoes, broccoli, spinach and black tea.
Quercetin rich foods by food group
- Capers and fresh herbs: raw and canned capers lead the USDA table, and fresh dill and cilantro follow.
- Onion family: red onions, onions overall, sweet onions and scallions all appear in the USDA table, from highest to lowest.
- Leafy and salad vegetables: radicchio, watercress, kale and red leaf lettuce rank well above romaine and spinach in USDA data.
- Other vegetables: hot yellow wax peppers, okra and asparagus.
- Berries and fruit: elderberries, cranberries, lingonberries and blueberries lead the fruit in the USDA table; apples with skin, cherries and strawberries are lower.
- Seeds, grains and cocoa: chia seeds, buckwheat and unsweetened cocoa powder, per USDA.
USDA groups quercetin with three other flavonols, isorhamnetin, kaempferol and myricetin, and its database covers 26 flavonoids across 506 foods. Our guide to foods high in antioxidants looks at the wider family, and our sibling list of foods high in resveratrol covers a compound that USDA’s flavonoid file does not include.
How onions compare by type
Onions are the highest-ranking food on the list that most people eat in real portions, and the USDA file separates them by type. Raw onions, with 400 samples, carry USDA’s top confidence code.
| Onion entry (USDA NDB No.) | Quercetin (mg/100 g) | Samples | Range (mg/100 g) |
|---|---|---|---|
| Onions, red, raw (99055) | 39.21 | 147 | 5.90 to 191.70 |
| Onions, cooked, boiled (11283) | 24.36 | 32 | 19.87 to 31.00 |
| Onions, raw (11282) | 20.30 | 400 | 1.50 to 90.75 |
| Onions, sweet, raw (11294) | 14.52 | 28 | 0.97 to 46.32 |
| Onions, spring or scallions (11291) | 10.68 | 4 | 0.00 to 18.00 |
| Onions, white, cooked, boiled (99082) | 10.55 | 6 | 8.70 to 12.40 |
In USDA data, red onions average nearly three times the figure for sweet onions, and the spread inside each type is wider than the gap between types. Our onions guide covers their other nutrients.
Why the numbers vary so much
USDA states plainly that considerable variation was observed in the flavonoid content of specific foods. USDA’s documentation explains that plants often produce flavonoids in response to environmental stresses such as diseases, insects, climate and ultraviolet radiation. USDA lists further sources of variability: cultivar, growing location, agricultural practices, processing and storage conditions, and preparation methods.
The ranges in the tables show the effect. Canned capers ran from about 45 to 520 milligrams per 100 grams across the 20 samples in the USDA file, and kale from zero to about 56. USDA notes that a zero in its table is a true zero, meaning the analysts looked for the compound and did not find it, while a missing value only means no data were available.
Raw versus cooked: what USDA cautions
The USDA table shows boiled onions averaging more than raw onions, and boiled asparagus slightly more than raw, while boiled broccoli averages less than raw. USDA warns users to exercise caution with such comparisons. USDA notes that values for different forms of a food may come from different sources, so a lower cooked figure does not necessarily mean cooking reduced the flavonoid, and a higher one does not show a gain. USDA says the comparison is valid only when paired raw and cooked samples are analyzed, so this list makes no claim about how cooking changes these foods.
How USDA reports and grades the data
- Unit: USDA reports mean values in milligrams per 100 grams of fresh weight of the edible portion, weighted for the number of samples in each study.
- Form: USDA explains that most flavonoids in food are bound to sugars as glycosides; it converted those values to the sugar-free aglycone form so that figures are consistent.
- Confidence code: USDA scores each study on sampling plan, sample handling, number of samples, analytical method and quality control, then grades the result from A, the highest, to D.
- Scope: USDA drew the data from published studies in the United States and other countries, so a figure may not match the produce in a given store.
- SR Legacy: the nutrient list in USDA’s SR Legacy release includes a quercetin field, but no food in the April 2018 release has a value in it.
Food first: what this list does not cover
This list is about food. It gives no intake target, because USDA publishes content data, not a recommended amount, and it makes no health promises. Capsules and powders are a separate subject with their own labels and cautions; our quercetin guide covers that side.
Frequently Asked Questions
Which foods high in quercetin top the USDA table?
Raw capers, canned capers, fresh dill, cilantro leaves and hot yellow wax peppers lead the USDA flavonoid table per 100 grams. Red onions lead the everyday vegetables.
Are onions among the quercetin rich foods?
Yes. In USDA data, raw red onions average 39.21 milligrams per 100 grams and raw onions overall 20.30, based on hundreds of samples.
Do apples belong on a list of quercetin foods?
Modestly. USDA lists 4.01 milligrams per 100 grams for raw apples with skin and 1.05 without skin, while apple skin alone averages 19.36.
Does cooking change the amount in a food?
The USDA table cannot answer that. USDA says raw and cooked values often come from different studies and are comparable only when paired samples are analyzed.
Does USDA SR Legacy list values for this flavonol?
No. SR Legacy has a field for it but no food values, so USDA’s separate flavonoid database, Release 3.3, is the source for this list.
Why do two sources give different numbers for the same food?
USDA attributes the variation to cultivar, growing location, farming practices, processing, storage and preparation, and it reports a minimum and maximum for each food.
Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a health condition. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Foods High in Resveratrol: What Published Studies Report, Quercetin: Benefits, Side Effects, Interactions and Bromelain Combos, Onion Benefits, USDA Onion Nutrition and Red vs White Onion, Foods High in Flavonoids: USDA Database Values by Subclass.