Found in Paraguay, a shrub known as Stevia is a result of researches carried out by a Spanish botanist Pedro Jaime Esteve. This shrub has been extensively used by the local people of the territory. It is used as a sweetener and the shrub is also used to control female fertility. Mixture of glycosides is usually what Stevia is. In stevia, many sugar molecules are attached to a non-carbohydrate moiety. This allows the compound to taste sweet, in fact it is found to be 40 times sweeter than sucrose.

Many toxicologists have researched on stevia side effects and a long continuous debate is now active on the safe usage of stevia. Researches with bacteria and cell cultures have shown that the compound is genotoxic in nature. It can change the genetic information without much work to be done. However, that was the case with bacteria. More detailed and sophisticated studies with mice claim that high concentrations of stevia can cause changes to the DNA and low concentrations have no affect whatsoever.

In the archives of toxicological databases, one can easily find numerous publications that primarily focus on the stevia side effects. In fact, controversies were created related to fertility and potential carcinogenicity. The results of the publications are not very consistent but there are ample proves of the usage being unsafe.

 A study done by researchers showed the decrease in sperm count of male rats when high amount of stevia was injected in them. A lot of toxicological studies do not confirm the probable mutagenicity but a few of them do. The research has never been conducted on humans directly but many authorities find the use of stevia as artificial sweeteners unsafe. Contrary to many authorities, there are some other authorities as well that have accepted stevia as a natural sweetener and have a completely different viewpoint about it.

FDA has approved stevia as nutritional supplement but not as a sweetener. Now, as all the supplements are known to have some adverse effects, stevia side effects come into picture too. Because there are not sufficient proofs to ensure its safety, many countries have banned using it. A latest research, however, has been performed by the European Food Safety Authority (EFSA) that has confirmed the safety of using stevia (at least under certain conditions). An acceptable intake of stevia as natural sweetener is considered safe now according to the latest research.