Side Effects of Cranberry Tablets

Cranberries may have therapeutic effects on the liver and stomach, as well as helping individuals with diabetes and urinary problems. Cranberry also may possess anti-cancer and antioxidant properties. This fruit, which comes from North America, has a variety of names including bog cranberry, American cranberry as well as its Latin name vaccinium macrocarpon. If you do not want to eat the bitter cranberries, you may derive their purported effects from taking a supplement of them. No matter how you ingest cranberries, you may experience side effects.

A bowl of fresh cranberries. (Image: matka_Wariatka/iStock/Getty Images)

Diarrhea and Upset Stomach

You may develop a bout of diarrhea as a common side effect of cranberry supplements because of the irritating effect on your intestinal lining. Any form of supplement including cranberry tablets may produce a disturbance in your digestive tract that may result in diarrhea while you adjust to it. This side effect should stop after a day or so. If it becomes bothersome and continues, call your doctor for help.You may also experience nausea or stomach upset when taking cranberry supplements. By consuming the cranberry supplement with food, you may avoid this side effect. Food will mix with the supplement in your stomach, preventing it from irritating your stomach lining. This may help you to feel better and avoid the nausea or stomach upset. If you do experience this side effect despite taking the cranberry supplement with food, you should notify your doctor at once and seek advice. Stop taking the cranberry supplement until you talk to your doctor.

Kidney Stones

Because of the high levels of oxalates in cranberries, the risk of having kidney stones increases. Oxalates occur in some foods and can cause the creation of calcium oxalate kidney stones that can produce excruciating pain when you need to pass them from your kidneys to your bladder and out the urethra. This tiny tube that carries urine from your bladder out of your body can become irritated and damaged because of kidney stones. Speak with your doctor about the potential for cranberry tablets to create kidney stones in your body.

Antacid Nullification

Cranberry supplements may decrease the effectiveness of antacid medications. Cranberries contain high levels of acids, and calcium, the chief ingredient in some antacids, is a non-acid base used to mix with the acids in your stomach to neutralize them. Take precautions when using cranberry tablets if you have a history of gastric reflux and use antacids to help combat it.


Cranberry tablets may cause serious side effects when combined with medicines such as warfarin. This medication is used to thin blood and decrease the risk of blood clots. Combining cranberry with warfarin may cause serious bleeding in some people. Talk to your doctor about your medications before you take cranberry tablets.

Load comments

Copyright © 2019 Leaf Group Ltd. Use of this web site constitutes acceptance of the LIVESTRONG.COM Terms of Use , Privacy Policy and Copyright Policy . The material appearing on LIVESTRONG.COM is for educational use only. It should not be used as a substitute for professional medical advice, diagnosis or treatment. LIVESTRONG is a registered trademark of the LIVESTRONG Foundation. The LIVESTRONG Foundation and LIVESTRONG.COM do not endorse any of the products or services that are advertised on the web site. Moreover, we do not select every advertiser or advertisement that appears on the web site-many of the advertisements are served by third party advertising companies.