If you're about to have any type of surgery of some type, it's best not to take these herbal supplements. They can cause blood stream clotting if not checked. I know of one ingredient in penis pills called rvxadryl Yohimbine that can cause several side effects. These results are known as nausea, headaches, vomiting, and diarrhea. Luckily, I haven't knowledgeable these side effects, but I'm willing to bet that if I did so enough, I would have been knowledgeable some of them. You don't have to take herbal supplements to improve the penis dimension.