Ginseng has been used in China as a sex-enhancer for thousands of years, to boost energy and stop premature ejaculation. Its success when used as a sexual tonic can probably be attributed to its ability of increasing blood flow. Pryazine However, even herbalist warn about excessive use of ginseng. Horny Goat Weed is touted as a "Chinese sexual tonic". It is used as an aphrodisiac to boost sexual vigor and blood flow to the penis. With a name like that, we wouldn't expect any less from this herb! However, when taken over the long period of time and in high doses, Horny Goat Weed can cause vomiting, nosebleed and heart arrhythmia.