Turmeric is widely considered to be a safe herb. That is, it has been used for many centuries in traditional medicine in India and other places in Asia, without widespread adverse reactions. And it has been tested scientifically in the West in the last 50 years or so, since becoming known in the health industry here. Again, without adverse effects.
But it has been found that occasional stomach upsets and disturbances of the gastrointestinal tract are two side effects of turmeric when its been taken over a long period in doses much higher than recommended.
I guess this side effect of turmeric is actually more about the person using the herb than the herb itself.
However, some people should avoid taking the herb. Because they will feel side effects of turmeric. The first of these are pregnant women, or women who are attempting to have a baby, or who have had trouble in the past becoming pregnant.
Also, women who are feeding breast milk to their babies, or who have a blood clotting propensity.
Also, if you are taking medication regularly it might be prudent to ask your doctor if they would create side effects of turmeric. But if he or she gives you the 'All clear' then go ahead and enjoy the many benefits of this amazing herb.
When you do that, however, make sure you take an adequate dose. The active ingredient in turmeric is curcumin. Look for a supplement using 95 percent curcumin. Or even more.
And since curcumin is not well absorbed when in tablet form, look for a supplement that contains piperine or bromelain that will assist in this.
One manufacturer that makes effective supplements which include generous amounts of high potency turmeric is located in my own city, here in New Zealand. You might want to look at my website for some more information about this.
Their flagship supplement, Total Balance, has turmeric with 98 percent curcumin, and piperine and bromelain to speed absorption. But it also contains much more -- in fact over 70 specialized nutrients including vitamins, minerals, antioxidants, amino acids, enzymes and herbs.