Background

Parsley (Petroselinum crispum) is an herb native to the Mediterranean that is grown worldwide. It's widely used in foods and also as medicine.

Parsley contains vitamins B1, B2, C, and K. Oils extracted from parsley contain chemicals that might help stimulate the appetite, improve digestion, and have laxative effects.

People use parsley for constipation, diabetes, dark skin patches on the face (melasma), kidney stones, and many other conditions, but there is no good scientific evidence to support these uses.

Don't confuse parsley with similarly named fool's parsley or parsley piert. These are not the same.

Safety Safety definitions

When taken by mouth: Parsley is commonly consumed in foods. Parsley is possibly safe when used in larger amounts as medicine, short-term. But using very large amounts of parsley, such as 200 grams, is likely unsafe. Parsley oil contains toxins that can cause serious side effects, including kidney and liver damage and hallucinations.

When applied to the skin: Parsley seed oil is likely unsafe. It can cause the skin to become extra sensitive to the sun. There isn't enough reliable information to know if applying parsley root and leaf to the skin is safe or what the side effects might be.

Special Precautions & Warnings:

Pregnancy: Parsley is commonly consumed in foods. But using parsley in larger amounts as medicine is likely unsafe during pregnancy. Parsley has been used to cause abortion and start menstrual flow. Also, taking large amounts of parsley during the first three months of pregnancy might increase the risk of birth defects. Stay on the safe side and stick with food amounts.

Breast-feeding: Parsley is commonly consumed in foods. But there isn't enough reliable information to know if parsley is safe to use in larger amounts as medicine when breast-feeding. Stay on the safe side and stick with food amounts.

Bleeding disorders: Parsley might slow blood clotting. Taking parsley might increase the risk of bleeding in people with bleeding disorders.

Fluid retention (edema): Parsley might cause the body to hold onto sodium (salt), which increases water retention.

High blood pressure: Parsley might cause the body to hold onto sodium (salt), which might make high blood pressure worse.

Kidney disease: Don't take parsley if you have kidney disease. Parsley contains chemicals that can make kidney disease worse.

Surgery: Parsley might lower blood sugar levels and interfere with blood sugar control during and after surgery. Stop using parsley at least 2 weeks before a scheduled surgery.

Effectiveness

Dosing & administration

Parsley is commonly consumed in foods. But as medicine, there isn't enough reliable information to know what an appropriate dose of parsley might be. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult a healthcare professional before using.

Interactions with pharmaceuticals

Aspirin

Interaction Rating=Minor Be watchful with this combination.

Some people are allergic to parsley. Aspirin might increase sensitivity to parsley, making allergic reactions worse. If you are allergic to parsley do not take aspirin and eat parsley.

Medications changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)

Interaction Rating=Moderate Be cautious with this combination.

Some medications are changed and broken down by the liver. Parsley might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

Medications for diabetes (Antidiabetes drugs)

Interaction Rating=Moderate Be cautious with this combination.

Parsley might lower blood sugar levels. Taking parsley along with diabetes medications might cause blood sugar to drop too low. Monitor your blood sugar closely.

Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)

Interaction Rating=Moderate Be cautious with this combination.

Parsley might slow blood clotting. Taking parsley along with medications that also slow blood clotting might increase the risk of bruising and bleeding.

Pentobarbital (Nembutal)

Interaction Rating=Moderate Be cautious with this combination.

Parsley juice might increase the amount of time pentobarbital stays in the body. Taking parsley along with pentobarbital might increase the effects and side effects from pentobarbital.

Sirolimus (Rapamune)

Interaction Rating=Moderate Be cautious with this combination.

Large amounts of parsley juice might increase levels of sirolimus in the body. This could increase the effects and side effects of sirolimus.

Warfarin (Coumadin)

Interaction Rating=Moderate Be cautious with this combination.

Warfarin is taken to thin the blood and slow blood clotting. Large amounts of parsley leaf might increase blood clotting. Taking parsley along with warfarin might decrease how well warfarin works to thin the blood.

Water pills (Diuretic drugs)

Interaction Rating=Moderate Be cautious with this combination.

Parsley seed extract might work like a "water pill" by causing the body to lose water, while parsley leaf and root might cause the body to hold on to water. Taking parsley along with "water pills" might interfere with the effects of these drugs.

Interactions with herbs & supplements

Herbs and supplements that might lower blood sugar: Parsley might lower blood sugar. Taking it with other supplements with similar effects might lower blood sugar too much. Examples of supplements with this effect include aloe, bitter melon, cassia cinnamon, chromium, and prickly pear cactus.
Herbs and supplements that might slow blood clotting: Parsley might slow blood clotting and increase the risk of bleeding. Taking it with other supplements with similar effects might increase the risk of bleeding in some people. Examples of supplements with this effect include garlic, ginger, ginkgo, nattokinase, and Panax ginseng.

Interactions with foods

There are no known interactions with foods.