Cucumbers: Nutrients, What Research Shows and Safety

Cucumbers (Cucumis sativus) are the fruit of a vine in the gourd family (Cucurbitaceae), eaten as a vegetable. The crisp, mild fruit is eaten raw, with or without the peel, and the same plant gives pickling types. People eat cucumbers for crunch, freshness and their high water content. This page keeps the food apart from extracts and hype, and says what the research does and does not show.

Read this first

• Cucumbers are an everyday food. As with any food, an allergic reaction is possible. For trouble breathing or swelling of the face or throat, call 911. See food allergy basics and emergency signs.
• Fresh cucumbers have been linked to Salmonella outbreaks. In 2024 the FDA and CDC tied 113 illnesses in 23 states to cucumbers from one grower. [6] Wash and scrub them, keep them cold, and do not eat recalled ones. [6][7]
• Raw cucumber has some vitamin K (USDA lists 16.4 µg per 100 g). People who take warfarin are told to keep vitamin K intake steady from day to day; ask your prescriber or pharmacist. [1][5]
• Honest summary: cucumber is a very watery, low-calorie food with a little of several nutrients. We found no human trial showing that it prevents or treats a disease; the "health benefit" papers are mostly lab and animal studies.

What is in it (USDA values)

Source: USDA FoodData Central, cucumber with peel, raw, SR Legacy item 168409 [1]. The per-serving figures are the per-100 g values scaled to the USDA household portion of 1/2 cup of slices (52 g). USDA also lists one whole cucumber (8-1/4 inch) as 301 g; that is about 41% of the Daily Value for vitamin K, 13% for copper and 9% each for vitamin C, potassium and magnesium. % Daily Value uses the FDA 2016 Daily Values; values vary with variety, ripeness and storage.

Plant compounds: USDA lists small amounts of carotenoids in raw cucumber (beta-carotene 45 µg and lutein plus zeaxanthin 23 µg per 100 g). [1] Reviews of the Cucumis genus describe hundreds of compounds, mostly triterpenoids called cucurbitacins, plus flavonoids and others, and report activity in cells and animals. They also say the mechanisms are not well understood and clinical studies are limited. [12] That is lab and animal evidence, not proof of an effect from eating cucumber.

What research says

Eaten as food vs taken as a supplement or extract. The findings above for peel extract, powder and cucurbitacins come from rats and cells, not from people eating cucumber slices. A result for a concentrated extract does not transfer to the food, and a food being watery or containing a nutrient does not prove it treats a disease. We found no cucumber-specific human trial for the topics on this page.

How much is a normal serving

The USDA household portions are 1/2 cup of slices (52 g) and one whole cucumber (8-1/4 inch, 301 g). [1] The WHO advises at least 400 g of fruits and vegetables a day for people older than 10, and the UK NHS counts 80 g of fresh, canned or frozen vegetables as one portion. [2][3] This is information, not a prescription. For pickled cucumbers, see pickles and fermented vegetables vs vinegar pickles. Cooking effects on cucumber nutrients: proper evidence not found in the sources we read.

Safety, allergy and medicines

• Allergy: the sources we read do not describe cucumber allergy in detail. Any food can cause an allergic reaction; for trouble breathing or swelling of the face or throat call 911. See food allergy basics and emergency signs.
• Warfarin and vitamin K: MedlinePlus says vitamin K can affect how warfarin works and that sudden changes in vitamin K intake can change the medicine's effect; people are advised to ask their provider about monitoring. [5] Cucumber is not listed there among the main vitamin K foods (leafy greens and the cabbage family are), but USDA lists 16.4 µg per 100 g, so a whole cucumber adds a noticeable amount. [1][5] See foods and medicine interactions.
• Salmonella and other food poisoning: the FDA outbreak investigation of November 2024 found 113 illnesses in 23 states and 28 hospitalizations, with no deaths, linked to American (slicer) cucumbers grown in Sonora, Mexico; recalls ran from 27 November to 9 December 2024 and the investigation closed on 8 January 2025. [6] Symptoms (diarrhea, fever, stomach cramps) usually start 12 to 72 hours after exposure; children under five, older adults and people with weakened immune systems are at higher risk of severe illness. [6] Lab work shows how this can happen: in one study, Salmonella put on cucumber flowers got inside a large share of the fruit, so surface washing may not remove all of it. [9] That is why recalls matter. If you have symptoms after eating a recalled cucumber, see a health care provider. [6]
• Peeling and cutting: a lab study found Salmonella can pass from the cucumber surface to the flesh and to the peeler during peeling. [8] The FDA advises washing produce before peeling or cutting even if you will not eat the skin. [7]
• Peel and wax: the FDA produce-safety page says to scrub cucumbers with a clean produce brush under running water. [7] Whether commercial wax coatings on cucumbers matter for health: proper evidence not found in the sources we read. Check the label or ask the seller if you want to know.
• Bitterness (cucurbitacins): cucumbers and their relatives can make bitter cucurbitacins as a plant defense. [11] A case report and review describe serious poisoning (stomach pain, vomiting, vomiting blood, low blood pressure, rarely death) after drinking bitter bottle gourd juice, a different gourd. [10] We did not find a source describing poisoning from eating bitter cucumber flesh specifically, so we make no claim either way; the safe practice is not to eat or drink anything from this family that tastes strongly bitter.
• Kidney disease and potassium: USDA lists 147 mg of potassium per 100 g (76 mg per 1/2 cup), a modest amount. [1] People on potassium-limited diets can see kidney disease, potassium and oxalates.
• Pregnancy: proper evidence not found in the sources we read for cucumber specifically. See foods in pregnancy: what official bodies advise.
• Extracts and supplements: peel and seed extracts are different from the food and their safety is not covered here. [12][13]

Choosing, storing and food safety

• Rinse cucumbers under running water and scrub with a clean produce brush; do not use soap or produce wash. Washing lowers bacteria but does not remove them all. [7]
• Wash before peeling or cutting, and cut away bruised or damaged parts. [7]
• Keep perishable and cut produce at 40°F (4°C) or below, and keep raw produce away from raw meat, poultry and seafood. [7]
• Check recall notices; do not eat recalled cucumbers or products made with them. [6]

Related pages

• Pickles and fermented vegetables vs vinegar pickles
• Foods and medicine interactions: vitamin K, grapefruit and others
• Fresh, frozen and canned produce
• Food storage, leftovers and food safety basics
• Food allergy basics and emergency signs