What are the disadvantages of coriander leaves?

December 8, 2025 •

4 min read

A staple in many global cuisines, coriander leaves (also known as cilantro) belong to the Apiaceae plant family, which includes other herbs like parsley and fennel. However, while generally safe in food amounts, some individuals experience a potent soapy taste due to a genetic predisposition, while for others, especially in large doses, the herb can trigger notable health disadvantages.

Quick Summary

Excessive consumption of coriander leaves can lead to allergic reactions, digestive distress, and dangerously low blood sugar or blood pressure in some susceptible individuals.

Key Points

Allergic Reactions: Some people, particularly those sensitive to other Apiaceae family plants, can experience skin rashes, itching, or respiratory issues from coriander.
Genetic Taste: A specific genetic variation (OR6A2) causes a significant portion of the population to perceive a soapy, unpleasant taste from coriander leaves.
Digestive Distress: Excessive consumption of coriander can cause gastrointestinal upset, including bloating, cramps, or diarrhea, due to its mild laxative properties.
Drug and Health Interactions: Coriander can lower blood sugar and blood pressure, potentially interfering with medications for diabetes and hypertension.
Increased Sun Sensitivity: The herb contains compounds that can make the skin more vulnerable to sunburn and photosensitivity after consumption.
Pregnancy and Surgery Risks: Due to effects on blood clotting, blood pressure, and blood sugar, excessive coriander use is cautioned against before surgery and during pregnancy.

Allergic Reactions and Sensitivities

While cilantro is a popular culinary herb, a segment of the population may experience allergic reactions upon consuming it or coming into contact with it. These allergies are often linked to a sensitivity to plants within the Apiaceae family, which also includes carrots, celery, and fennel. Symptoms can vary widely, from mild discomfort to severe, life-threatening reactions. For those with known allergies to other members of this plant family, exercising caution with coriander is highly advisable due to the potential for cross-reactivity.

The Genetic Factor: Why Coriander Tastes Soapy

One of the most widely known "disadvantages" of coriander leaves is not a health risk but a matter of perception, driven by genetics. For approximately 10-15% of people, coriander leaves have a strong, unpleasant soapy taste. This is caused by a genetic variation related to the olfactory receptor gene OR6A2, which makes some people highly sensitive to the aldehyde compounds present in both coriander and soap. This gene variation explains why a herb that is a delicious garnish for some is an inedible ingredient for others.

Key Symptoms of Coriander Allergy

For those who are truly allergic, symptoms can appear shortly after exposure. It's crucial to be aware of the signs to seek medical attention if necessary.

Hives and skin rashes
Itching or swelling of the face, lips, tongue, or throat
Nasal congestion or asthma-like symptoms, such as wheezing and shortness of breath
Gastrointestinal issues, including nausea, vomiting, and abdominal pain
In severe, but rare, cases, anaphylaxis

Potential Digestive Issues

Although coriander is traditionally used to aid digestion, excessive intake can have the opposite effect for some. Large quantities may act as a mild laxative, causing gastrointestinal distress such as bloating, stomach cramps, and diarrhea. Individuals with sensitive stomachs or pre-existing conditions like Irritable Bowel Syndrome (IBS) should consume coriander in moderation to avoid aggravating their symptoms. Overconsumption, particularly of concentrated seed water, can lead to digestive irritation.

Interactions with Medications and Health Conditions

Coriander's potent medicinal properties mean it can interact with certain medications and pose risks for those with specific health conditions.

Blood Sugar: Coriander has been shown to lower blood sugar levels. This can be beneficial for some, but for individuals on diabetes medication, consuming large amounts could lead to hypoglycemia (dangerously low blood sugar). Careful monitoring of blood sugar is essential.
Blood Pressure: The herb can also decrease blood pressure. Those with low blood pressure or taking antihypertensive drugs could experience blood pressure that is too low, leading to dizziness or other complications.
Sedatives: Coriander might cause sleepiness. When combined with sedative medications, it could increase drowsiness to a dangerous level.

Risks During Pregnancy and Surgery

Medical professionals advise caution with coriander during specific life stages and procedures.

Pregnancy and Breastfeeding: There is insufficient reliable information on the safety of coriander during these periods. Some sources suggest that excessive amounts might induce uterine contractions. It is best for pregnant or breastfeeding individuals to stick to food amounts and consult a doctor.
Surgery: Due to its effects on blood sugar, blood pressure, and blood clotting, coriander can interfere with surgical procedures. Patients should stop consuming large amounts of coriander at least two weeks before a scheduled surgery.

Skin and Photosensitivity Problems

Some individuals may experience skin-related issues from consuming or handling coriander. This can manifest as skin irritation or dermatitis. Furthermore, coriander contains compounds called psoralens, which can increase sensitivity to sunlight (photosensitivity). For those who are susceptible, this can raise the risk of sunburns or other sun-related skin damage.

Caution for Individuals with Kidney Concerns

While coriander is a diuretic that can be beneficial for healthy kidneys, it is not recommended for those with chronic kidney disease (CKD). Coriander leaves have relatively high levels of potassium, and individuals with CKD cannot process potassium efficiently. For those with kidney issues, even a small amount may add to the accumulated toxins in the body.

Comparison of Moderate vs. Excessive Coriander Consumption


Feature	Moderate Intake (Food Amounts)	Excessive Intake (Therapeutic/High Doses)
Allergic Reactions	Highly unlikely unless allergic.	Increased risk of allergic symptoms.
Digestive Impact	Often aids digestion.	Risk of bloating, cramps, or diarrhea.
Blood Sugar/Pressure	Minor or negligible effect.	Potential for significant drop (hypoglycemia, hypotension).
Photosensitivity	Minimal risk.	Increased risk of sun sensitivity and sunburn.
Drug Interactions	Generally safe.	High risk of interacting with diabetes, blood pressure, and sedative medications.
Kidney Strain	Beneficial for healthy kidneys.	Potential strain due to high potassium, especially for those with CKD.

Sourcing and Food Safety

As with any raw produce, there is a risk of bacterial or parasitic contamination with coriander leaves. Outbreaks linked to the parasite Cyclospora have been reported in the past. It is crucial to wash coriander leaves thoroughly before use to minimize this risk. Sourcing from a reputable provider is also important.

Conclusion: Weighing the Benefits Against the Risks

While coriander leaves are a flavourful and nutritious herb for most, a variety of disadvantages exist for others. These range from a harmless, genetically-determined soapy taste to serious health concerns like allergic reactions and dangerous interactions with medication. Individuals with diabetes, low blood pressure, or chronic kidney disease should exercise particular caution, while pregnant women and those facing surgery should consult a healthcare provider. For everyone, moderation and proper food hygiene are key to safely enjoying this versatile herb.

Note: It is crucial to discuss any dietary changes or concerns with a healthcare provider, especially if you are taking medication or have underlying health conditions. For more information on potential drug interactions with coriander, refer to sources like RxList.

Frequently Asked Questions

The dislike for coriander's taste is primarily a genetic trait. It is linked to a variation in the OR6A2 gene, which makes some people more sensitive to the aldehyde chemicals that give the herb its distinctive, and sometimes perceived as soapy, flavor.

Yes, some people can be allergic to coriander, especially if they have sensitivities to other plants in the Apiaceae family (like caraway or fennel). Symptoms can include hives, swelling, and respiratory issues.

Yes, excessive intake of coriander, particularly in concentrated forms, can cause digestive distress such as bloating, stomach cramps, and diarrhea, due to its natural laxative effects.

Coriander has properties that can lower both blood pressure and blood sugar. Therefore, individuals with low blood pressure or those taking medication for diabetes should use caution and monitor their levels carefully, consulting a doctor before consuming large amounts.

While coriander in food amounts is generally considered safe, there is a lack of reliable information regarding larger medicinal doses during pregnancy. Some sources suggest excessive amounts could stimulate uterine contractions. It is best to consult a doctor.

Coriander can lower blood sugar and blood pressure and may also slow blood clotting. These effects can interfere with surgical procedures, so it is recommended to stop consuming large amounts at least two weeks beforehand.

Yes, coriander contains compounds that can lead to photosensitivity, which increases the skin's vulnerability to sunburn, especially with excessive consumption.