Black Seed Oil Side Effects: What to Know Before You Start

At label servings, most people who take black seed oil notice nothing worse than an aftertaste or burps. Some report nausea or bloating. On skin, it can cause an itchy rash in some people, so patch-test first. Ask your doctor before using it if you're pregnant or nursing, have surgery coming up, or take prescription medication.

What are the most common side effects of black seed oil?

Side effect	When it shows up	What helps
Burps and a cumin-like aftertaste	The most common complaint, especially without food	Take it mid-meal, split the serving, or switch to softgels
Nausea or bloating	Reported by some people taking it by mouth	Take it with food; start with half a serving
Itchy rash (contact dermatitis)	Applying the oil directly to skin	Patch-test first; stop if your skin reacts

Last checked: October 2026. Source: WebMD, medically reviewed March 2026; burps from user reports on r/Supplements.

If the taste and burps are what bother you, our guide on how to take black seed oil without the taste has the practical fixes.

Who should talk to a doctor before taking black seed oil?

These come from WebMD's medically reviewed guidance and the same cautions we print for our own softgels. Ask first if any of these apply to you:

• You're pregnant or nursing. Black seed used in cooking is different from a concentrated oil taken every day. WebMD notes that large amounts may affect uterine contractions.
• You have surgery coming up. WebMD advises stopping black seed at least two weeks before surgery and telling your doctor how much you take.
• You take medication for blood pressure, blood sugar or blood thinning. Black seed may add to the effect of these medicines. Bring the Supplement Facts panel to your doctor or pharmacist.
• You have a bleeding disorder. WebMD notes black seed might slow blood clotting.
• You take other prescription medication. Ask your pharmacist about interactions. Don't stop anything you've been prescribed in order to take a supplement.

Can I put black seed oil directly on my skin?

Many people do, but it's a strong oil, and WebMD lists contact dermatitis (an itchy rash) as a possible reaction. Patch-test before you use it on your face or a large area:

1. Dab a small amount on the inside of your forearm.
2. Leave it for 24 to 48 hours without washing it off.
3. If you see redness, itching or bumps, don't use it.

If you'd rather use it in a finished skincare product, our guide to black seed oil for skin covers how people use it.

How can I lower the chance of side effects?

• Stick to the label. More is not better, and stacking several black seed products adds up fast.
• Take it with food. This is the biggest single fix for stomach complaints and burps.
• Start low. Half a serving for the first few days lets you see how you react.
• Change one thing at a time. If you start several supplements at once, you won't know which one disagrees with you.
• Use fresh oil. Rancid oil tastes worse and is worth throwing out. See how to tell if black seed oil has gone rancid.

Quick answers

Is it safe to take black seed oil every day?

Most labels are written for daily use at the listed serving. Follow yours, and ask your doctor first if you take medication or are pregnant or nursing.

Can black seed oil upset your stomach?

Some people report nausea or bloating. Taking it mid-meal and starting with half a serving usually helps.

Why do I burp after taking black seed oil?

It's an oil with a strong flavor, and it can repeat on you, especially on an empty stomach. Take it with food, split the dose, or try cold softgels.

Can I take black seed oil while pregnant?

Ask your doctor or midwife first. Black seed as a cooking spice is not the same as a daily concentrated oil.

Can you take too much black seed oil?

Yes. Stay at the label serving. WebMD notes older research linking large daily amounts (about 2,000 to 2,500 mg) to effects on the kidneys, so don't go past your label without your doctor's advice.

This guide is general information, not medical advice. If you decide black seed oil is right for you, SMAMES softgels are two a day with a meal, and the Supplement Facts panel is on the product page so you can show it to your doctor. Everything we make with black seed oil is in our black seed oil collection.