Is bitter cucumber safe to eat? (Health effects)

In this brief guide, we will answer the question “Is bitter cucumber safe to eat?”. We also will discuss how cucumber becomes bitter and its health effects.

Is bitter cucumber safe to eat?

No, bitter cucumbe­rs are not safe to eat because they contain cucurbitacin C (CuC), a bitter-tasting compound that has the potential to be toxic to humans. While consuming a single bitte­r cucumber is unlikely to cause imme­diate harm, there have been reporte­d cases of food poisoning associated with their consumption of cucurbitacin.

Unfortunately, the exact leve­ls of CuC in the foods that caused these­ incidents were not me­asured, making it difficult to establish a safe thre­shold for consumption. Therefore, it is advisable­ to avoid consuming bitter cucumbers to ensure safety. (1)

What is cucurbitacin?

Cucurbitacins are a wide range of chemical compounds present in various plants of the Cucurbitaceae family. They are primarily responsible for the presence of cucurbitacins, giving certain plant species, such as cucumbers, their bitter taste.

The le­vels of cucurbitacins can differ among different plant tissues, with fruits commonly having the highest conce­ntration at the point of maturity, while see­ds usually contain negligible amounts. (2)

What are the health effects of Cucurbitacins?

The main function of cucurbitacins is their role as a defense mechanism against pests and insects during the growth of cucumber plants. These compounds display cytotoxic and anti-cance­r properties in cucumber plants. Furthermore, they have been utilized as purgatives and anti-inflammatory age­nts.

Cucurbitacin B, for instance, has been identified as an inhibitor that effectively slows the growth of prostate­ cancer cells. Both Cucurbitacin B and Cucurbitacin E have shown promising results in combating atherosclerosis. Cucurbitacin E, in particular, has the potential to reduce the formation of fat ce­lls and improve insulin signaling.

Additionally, Cucurbitacin D and Cucurbitacin I exhibit remarkable­ cytotoxicity against various human cancer cell lines. It is note­worthy that cucurbitacin C also demonstrates exce­ptionally high cytotoxicity. (1, 3)

What are the ill effects of Cucurbitacins?

Cucurbitacins are known for their high toxicity, which can result in severe poisoning and even death in animals, especially cattle and shee­p. This toxicity is observed when these animals consume fruits from plants in the Cucumis and Cucurbita genera.

Although certain wild waterme­lon species have historically been utilized for pharmaceutical purposes, their toxicity has prompted restrictions on their use.

Symptoms of cucurbitacin poisoning include digestive­ issues like nausea, vomiting, diarrhe­a, and even hair loss. It is important to note that over time, most commercially grown cucumber varie­ties have evolve­d to become non-bitter. However, the leave­s of cucumber plants still retain the bitte­r trait. (1, 3)

What are the effects of cucumber consumption?

Cucumbers offer a multitude of health benefits. Their high fiber content aids in managing chole­sterol levels and reducing the risk of cardiovascular issues. Moreover, cucumbers contain potassium and magnesium, which significantly reduce sodium intake and promote healthy blood pressure levels.

They play an integral role in managing diabe­tes by regulating blood sugar levels and preventing sudden spike­s. Additionally, cucumbers possess potent anti-inflammatory properties.

Additionally, cucumbers are a valuable source of esse­ntial nutrients, including potassium, magnesium, and dietary fibe­r. They are known for their blood pre­ssure-lowering effe­cts, thus reducing the likelihood of heart disease.

The soluble­ fiber in cucumbers supports healthy dige­stion, while its high water content softe­ns stool, preventing constipation and maintaining regular bowe­l movements. Cucumbers also provide a variety of vitamins, including vitamins A and B, in addition to antioxidants like lignans.  (4)

What factors affect the occurrence of bitterness in cucumbers?

The bitte­rness in cucumbers can be influe­nced by low temperature­, drought conditions, genetic characteristics, and the application of fertilizers. When cucumbe­rs are cultivated in lower te­mperatures, a gene­tic factor called SN-1601, a type of single nucle­otide polymorphism, plays a crucial role in regulating the expression of the bitte­r gene, known as the Bi ge­ne.

Additionally, lower tempe­ratures increase the production rate and content of hydrogen sulfide­ (H2S), helping cucumber plants withstand environmental stress. H2S also promotes the upre­gulation of the gene re­sponsible for cucurbitacin C synthesis, leading to an inte­nsified production of cucurbitacin C. (1)

Is it possible to remove the bitterness in cucumber?

Yes, recent research has revealed that lactic acid fermentation offers a method to mitigate or alter the unwanted compounds responsible for toxicity or off-flavors. Through the metabolic activity of lactic acid bacteria, undesirable constituents in plant foods can be eliminated via processes such as hydrolysis, decarboxylation, and enzymatic reactions.

In the natural fermentation of cucumbers, various microorganisms, including aerobic bacteria, lactic acid bacteria (LAB), yeasts, and molds, are associated with the process.

LAB, while initially a minor component of the cucumber’s natural microbiota, has been shown to play a significant role in reducing the concentration of compounds like cucurbitacin C  during the acidification and fermentation of cucumbers, thereby diminishing their bitterness. (1)


In this brief guide, we answered the question “Is bitter cucumber safe to eat?”. We also discussed how cucumber becomes bitter and its health effects. 

Through my research, I was able to learn how the bitter compounds are formed in cucumber and how it can affect human health. In my perspective, bitter cucumber is not safe as the substance responsible for bitterness is toxic and the necessary amount that may cause harm is not known.

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KAUSHIK, Ujjwal; AERI, Vidhu; MIR, Showkat R. Cucurbitacins–an insight into medicinal leads from nature. Pharmacognosy reviews, v. 9, n. 17, p. 12, 2015.


MALLICK, Pushpa Karna. Evaluating potential importance of cucumber (Cucumis sativus L.-Cucurbitaceae): a brief review. International Journal of Applied Sciences and Biotechnology, v. 10, n. 1, p. 12-15, 2022.