Zucchini: Nutrition, Benefits, Calories and Bitter Squash Safety

Zucchini is a summer squash: a tender, mild green vegetable from the gourd family that is eaten skin, seeds and all. It is mostly water. USDA data put raw zucchini at about 95% water and 17 calories per 100 grams, and a medium zucchini of about 196 grams has roughly 33 calories, 2 grams of fiber and about 39% of the Daily Value for vitamin C. Below are the USDA zucchini nutrition facts raw and cooked, what the zucchini benefits claims actually rest on, how it compares with other vegetables, and one safety point every gardener should know: a zucchini that tastes strongly bitter should not be eaten.

Peptide Labs does not sell zucchini or zucchini products. This article is general nutrition information, not medical advice.

What is zucchini?

Zucchini (Cucurbita pepo), called courgette in Britain, is a summer squash picked young while the skin is thin and the seeds are soft. Botanically it is a fruit, because it grows from the flower and holds seeds, but in the kitchen it is cooked and eaten as a vegetable. It belongs to the same species as many pumpkins and other summer squashes such as yellow crookneck and pattypan, and to the same plant family as cucumbers and melons. The seeds sold as snacks in our pumpkin seeds guide come from close relatives. Dark green is the usual color, though golden and striped types are common at farmers markets.

Zucchini nutrition facts from USDA

The table uses the USDA FoodData Central SR Legacy entries for zucchini with skin, raw (FDC 169291) and boiled and drained without salt (FDC 169292). Percent Daily Values use the FDA Daily Values for adults and children 4 years and older.

Vitamin C is the main contributor, and some of it ends up in the cooking water: per 100 grams, USDA lists 17.9 milligrams of vitamin C for raw zucchini and 12.9 milligrams for boiled. The boiled entry lists more vitamin A per 100 grams than the raw one (56 versus 10 micrograms RAE in USDA data); the two entries come from different samples, so small raw-versus-cooked gaps should not be read too closely. Zucchini also supplies lutein and zeaxanthin, about 4,165 micrograms per medium squash in USDA data, two carotenoids with no Daily Value that our lutein guide covers.

Zucchini benefits: what the evidence supports

We found no human trials that test zucchini on its own, and claims that it melts belly fat, cleanses the body or controls blood sugar go well beyond any evidence. What zucchini does offer is plain in the nutrition data:

• Volume for few calories: at about 95% water, a cup of chopped raw zucchini has roughly 21 calories, so it adds bulk to pasta, stir-fries and egg dishes. Our low-calorie snacks guide uses the same idea.
• Low in carbohydrate: a boiled cup has under 5 grams of carbohydrate in USDA data, a small fraction of the 25 to 31 grams in a cooked cup of corn or peas. That is why zucchini shows up on low-carb food lists and why our starchy vegetables guide uses it as a comparison.
• Vitamin C and potassium: a medium zucchini supplies about 39% of the vitamin C Daily Value and 11% of potassium. For richer sources, see our guides to vitamin C foods and potassium foods.
• Some fiber: about 2 grams per medium zucchini, less than many vegetables. Our high-fiber foods guide lists bigger sources, and our fiber intake guide explains the Daily Value.
• Easy on many digestive systems: Monash University’s sample list, summarized in our low FODMAP diet guide, places zucchini among lower-FODMAP vegetables, although Monash rates foods by serving in its app and warns that FODMAP content cannot be guessed.

How zucchini compares with other vegetables

Per 100 grams raw, zucchini sits in the same watery, low-calorie group as cucumber, tomato and pepper. The table uses USDA SR Legacy values.

Zucchini and yellow summer squash are close to interchangeable. Eggplant, covered in our sibling eggplant guide, has three times the fiber per 100 grams, and green bell pepper is the clear vitamin C leader. Tomatoes, peppers and eggplant belong to the nightshade family; zucchini does not, a question that comes up often among readers of our nightshade guide.

Raw zucchini vs cooked, and how to use it

• Raw zucchini: it can be eaten raw, sliced thin into salads or spiralized into noodles. Wash it first and taste a small piece; see the bitterness section below.
• Cooked: sauteing, roasting and grilling keep it firm, while boiling softens it and moves some vitamin C into the water, as the USDA numbers above show.
• Skin and seeds: both are edible in young zucchini; very large, overgrown squash have tougher skin and bigger seeds.
• Recipes change the numbers: zucchini bread, fritters and fried zucchini get most of their calories from flour, sugar and oil, not from the squash.
• Smaller appetites: watery vegetables are an easy way to add volume to smaller meals, a theme in our GLP-1 diet guide.

Bitter zucchini and cucurbitacin poisoning

Plants in the gourd family can make cucurbitacins, intensely bitter compounds that discourage insects and other animals from eating them. Zucchini normally tastes mild, but occasionally one turns out strongly bitter, and eating it can cause food poisoning that one 2022 case report title calls toxic squash syndrome.

• A documented case: a 2020 case report in a German-language medical journal described a 66-year-old woman admitted to an emergency department after eating bitter zucchini. She had nausea, vomiting, bloody diarrhea, dehydration, low blood pressure and a fast heart rate, and ultrasound showed inflammation of the colon. She improved with intravenous fluids and could eat again after two days.
• How common: the authors call this poisoning rare and note that it can occur with produce from small home gardens in hot weather. A 2024 review from the Marseille poison control center in southeastern France logged 2,197 cases over 22 years in which people ate a poisonous plant by mistake; plants of the gourd family were the second most frequent group, at 3.3%.
• Taste is the warning sign: the 2020 report stresses that a bitter taste is the key clue to this poisoning. If a zucchini or other squash tastes strongly bitter, spit it out and throw the rest of that squash away rather than trying to cook the bitterness out.
• If symptoms start: vomiting, diarrhea or stomach cramps after eating bitter squash warrant a call to Poison Help at 1-800-222-1222 in the US. Bloody diarrhea, fainting or signs of dehydration need urgent care.

Zucchini allergy and other cautions

• Oral allergy syndrome: the American Academy of Allergy, Asthma and Immunology says ragweed pollen cross-reacts with banana, cucumber, melon and zucchini, which can cause itching or swelling of the mouth, lips, tongue and throat. Heat breaks down the proteins involved, the academy notes. Throat swelling or trouble breathing needs urgent care, and an allergist can confirm the cause.
• Labels: zucchini is not one of the nine major food allergens that US labels must declare, so people who react need to read ingredient lists on mixed dishes and baked goods.
• Potassium limits: people whose clinician has asked them to limit potassium, for example because of kidney disease, can ask how zucchini fits; a medium squash has about 11% of the Daily Value.
• Suspected reactions: our elimination diet guide explains why food testing should be supervised rather than done alone.

Frequently Asked Questions

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 food allergy. 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: Eggplant Benefits and Nutrition: USDA Facts, Nasunin and Allergy, Starchy Vegetables: List, USDA Nutrition and Non-Starchy Swaps, Low Calorie Snacks: USDA Calories per Serving and 100-Calorie Portions, Spaghetti Squash: Calories, Nutrition and How It Compares to Pasta.