Sarsaparilla is a climbing, evergreen vine found in Australia, Southeast Asia, Jamaica and the rain forests of South and Central America. If you’ve ever sampled old-fashioned root beer, then you’re familiar with the unique aroma and flavor of the plant’s root. The root has also been used for centuries as an aphrodisiac and blood toner, and to treat skin disorders, inflammatory diseases and syphilis. As with all medicinal herbs, sarsaparilla root may produce side effects.

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If you are experiencing serious medical symptoms, seek emergency treatment immediately.

Allergic Reactions

Some people may have an allergic reaction to sarsaparilla root preparations, such as hives or skin rash. Inhalation of sarsaparilla root may trigger an asthma attack, according to a paper published in a 1996 issue of the "Journal of Allergy and Clinical Immunology." If you experience chest pain, swelling of the tongue or shortness of breath, seek immediate medical attention 1.

Gastrointestinal Effects

According to the “Physicians’ Desk Reference for Herbal Medicines,” sarsaparilla root contains the steroid saponins, which can irritate the lining of the stomach 2. You may need to consume large amounts of products flavored with sarsaparilla root extract to experience this effect, however. Most people tolerate it with no abdominal problems.

Kidney Irritation

Sarsaparilla root saponins are responsible for producing diuretic effects, meaning that they increase the production of urine, according to the "Physicians' Desk Reference for Herbal Medicines." This could potentially irritate the kidneys. Avoid sarsaparilla root if you have a history of kidney disease.

Hormonal Effects

One of the steroid saponins found in sarsaparilla root is diosgenin, the same compound found in Mexican yam. Diosgenin is a building block essential for the production of steroid hormones, namely estrogen, testosterone and progesterone. The University of Maryland Medical Center explains that this conversion doesn’t take place in the body, though, and that the only way to get these hormones from diosgenin is by chemical synthesis in a lab. While many proponents of sarsaparilla root insist that the aphrodisiac properties of the herb are due to the presence of progesterone in the root itself, this isn't the case.

Likewise, some body builders claim that sarsaparilla root increases muscle mass due to being a rich source of testosterone, while others contend that menopausal symptoms in women are reduced due to estrogenic activity. Michael T. Murray, N.D., author of “The Healing Power of Herbs,” puts the argument to rest by clarifying that sarsaparilla root does not contain testosterone or estrogen 3.

The University of Maryland Medical Center points out that, since diosgenin is the same substance used to produce the first birth control pills of the 1960s, it may produce estrogen-like effects in the body. This is because diosgenin interacts with estradiol, a natural hormone produced by the body that is also found in certain medications. Avoid sarsaparilla root if you take oral birth control medications or are undergoing hormone replacement therapy or treatment for a hormone-driven cancer.