Penis enlargement is safe when done correctly. However the possibility for injuries are very real if done improperly. The biggest issue I have seen from guys over the years is rushing in and doing too much, too fast. Most guys want resultsnow, and will push way too hard to try and get them as fast as possible. Those are the ones who end up hurting themselves and will tell you that penis enlargement is a bunch of bunk that will only lead to injury. When done properly, you will have a penis that is performing at 100% and will slowly grow in both length and girth.
Short of cosmetic, reconstructive surgery, there's not really much you can do. There are no magic pills – drugs or herbal – that are going to do it for you. Any of these that have any actual safe effects just promote effective blood flow within the penis, which is what's responsible for causing an erection. Increasing the bloodflow safely in the penis will allow the fullest erection you can physically have, or might prolong erection. But you can't get a bigger penis in this way safely.
Consider ginkgo biloba. This herb is often taken to boost memory, but it also help with blood circulation and may enhance blood flow to the penis. According to a study conducted at the University of California, ginkgo is most effective at helping men on anti-depressants that can lead to sexual dysfunction. Another study found that gingko had no effect. Scientific data is inconclusive, but since gingko enhances memory and has relatively few side effects, it might be worth a try.