In today's stressful world, sex can often be the last thing on the day's agenda. When the sparks fizzle in the bedroom, herbal supplements may be the answer.There are lots of natural herbal supplements to boost the sex drive in both men and women. These herbs can help promote a sense of well-being and even increase the amount of testosterone and estrogen in the body.MacaThe Discovery Health channel website calls Peruvian maca "nature's Viagra." The dried root of the maca plant is used to stimulate libido and increase sexual function.Maca has been found to stimulate the production of hormones in the body that help increase the sexual appetite in both men and women. The website reports that two compounds found in the maca plant, madamides and macaenes, help stimulate sexual function in men and women.YohimbeYohimbe has comes from the bark of a tree that grows naturally in West Africa, and the Science Channel website notes that supplementing the diet with the herb can give men suffering from erectile dysfunction the ability to achieve erections.Experts believe that yohimbe stimulates specific nerve centers along the spinal column that control erection. Women also benefit from taking yohimbe because it helps stimulate sensation in the genital organs, according to the Libido Increasing Foods website.Horny Goat WeedHorny goat weed has been used as an aphrodisiac for centuries in China and grows at high altitudes in Asia. The Discovery Health website says that while it is not clear exactly how horny goat weed works, it has been shown to boost libido, increase the likelihood of erection and minimize the symptoms of menopause.The plant contains a chemical called icariin that helps promote the production of testosterone in both men and women, helping stimulate sexual appetite.