We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What are the Most Common Flaxseed Side Effects?

By Kerrie Main
Updated: Mar 03, 2024

Flaxseed is a popular nutritional supplement found in a wide variety of foods and health products. Flaxseed and flaxseed products have many beneficial components, such as antioxidants, fiber and omega-3 fatty acids, but some users experience side effects from them. Some of the most common flaxseed side effects include bowel irritations and nutritional absorption problems. These particular side effects typically occur when too much flaxseed is taken.

The ancient Babylonians first cultivated flaxseed in 3000 B.C., and it has been revered as a useful health supplement since then. Flaxseed comes from a small, annual plant that has blue flowers and thin leaves. The actual flaxseed usually is brown or golden in color. Flaxseed might be consumed as a whole intact seed or in the forms of ground meal, powder and oil.

Flaxseed has many nutritional components and features. It contains protein, vitamin E, vitamin B, calcium, iron, sterols, potassium, antioxidants and alpha-linolenic acid (ALA), which is an essential omega-3 fatty acid. When in seed, ground meal or powder form, flaxseed contains both soluble and insoluble fiber daily requirements. The high-fiber properties make flaxseed a common aid for constipation and digestion health problems.

The recommendation for adults is one or two tablespoons (14-28 g) of ground flaxseed per day. When larger quantities are taken, flaxseed side effects might include worsened constipation or intestinal blockages. Sometimes the fiber in flaxseed hinders the body’s ability to absorb other oral medications taken by the person. Other flaxseed side effects are diarrhea and hormonal imbalance.

There are several ways to prevent the most common flaxseed side effects. For example, when consumed in oil form, flaxseed does not have dietary fiber. Some people grind the flaxseed themselves to ensure that they do not exceed the daily requirements. Others keep a list of everything they eat in a day to keep track of how much flaxseed they’ve actually eaten. This can be helpful because many common products, such as oatmeal, cereal and muffins, already have flaxseed added to them.

People should consume plenty of water when eating products with flaxseed or taking flaxseed supplements. This can help to prevent the flaxseed side effects of constipation and irritated bowels. Another way to avoid issues is for people to talk to their doctors about any and all complementary medicines and supplements they take. Most health practitioners will be able to see potential problems and risks of combining certain medications or vitamins with flaxseed.

The Health Board is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
By anon941532 — On Mar 23, 2014

I've been terrified at how thirsty I've been lately, and it just occurred to me that it could be the addition of large quantities of flax into my diet. Thanks to all who posted about that.

By anon940695 — On Mar 19, 2014

Flax seed is a soluble fiber which means it absorbs water and turns into a gel like substance in the bowel. Soluble fiber is healthy for the bowel as it bulks up the stools (which promotes regular soft bowel movements) and researchers think it also cleans the bowel and this prevents diseases of the bowel.

The thing with flax seed is that it is highly absorbent and sells up eight times its dried size. If you don't drink enough fluid, it may dry out your bowels as it may suck up the fluid around it. A lot of drier types of food have this effect in the bowel if people do not drink enough fluids.

I once put some out of date flax seed in the hanging bird feeder and after it rained it swelled up and blocked up the feeder. It had turned to soft goo (and this goo is excellent when its in our bowels). I don't think any of the birds ate it, but the experience helped me understand soluble fiber.

By bear78 — On May 02, 2013

@alisha-- That's odd, I've never heard of headaches as a side effect before. Are you taking ground flaxseed or flaxseed oil? I wonder if you're allergic to it.

By discographer — On May 02, 2013

@fBoyle-- Yea, those are extremely common side effects of flaxseed. I have them too. Fiber in general is difficult to digest and increases the need of water. I have these side effects with all high fiber foods, not just flaxseed so I think they're normal.

I have started experiencing one other symptom lately though, which is headache. I'm not certain that it's the flaxseed but I'm not taking any other supplement or medication so I'm guessing that's what causing it. I'm going to take a break from it for a few weeks and see if the headache disappears.

By fBoyle — On May 01, 2013

If I have whole flaxseed, I have digestion problems and bloating. I don't have these issues if I grind the flaxseeds first. It's like my body can't digest it in whole form.

I also feel extremely thirsty after having flaxseed. My mouth dries up and I feel like I haven't had water in days. I usually go through two to three glasses of water immediately after a meal with flaxseed.

Is everyone else the same way?

The Health Board, in your inbox

Our latest articles, guides, and more, delivered daily.

The Health Board, in your inbox

Our latest articles, guides, and more, delivered daily.