I've been using mukta vati for some time, and to say it has no side effects is a complete fallacy. Nasal congestion is a side effect I, and reviewers at Amazon have suffered from using this product. I can't take more than 2 a day, or I get sinus headaches from nasal congestion. 2 a day doesn't get my pressure low enough, so I take then in combination with low dozes of my prescription medication and this works very well for me. Anything the body reacts to, the body can react negatively to. Natural cures can, and do have side effects for some people just like prescription medications.