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What is Spanish Fly? Does it Work?

Mike Bohl, MD, MPH, ALM

Reviewed by Mike Bohl, MD, MPH, ALM

Written by Geoffrey Whittaker

Published 11/02/2021

Updated 01/10/2024

For centuries, people have turned to aphrodisiacs in an attempt to boost their sex drive and enhance their sex appeal. Our ancestors ate oysters or chewed special plants — some found even weirder things they believed would give them a bedroom boost. 

Spanish fly is one such aphrodisiac. Made famous by Bill Cosby in a (now obviously super controversial) stand-up routine from the 1960s, Spanish fly refers to all sorts of tonics, potions and other “love supplements” made from one type of insect: blister beetles. 

Spanish’s fly’s reputation isn’t the best — and not just because beetles aren’t actually flies. This buggy “treatment” is linked to a long list of potential side effects, some of which can be deadly. Meanwhile, there’s only limited scientific evidence that it has much of an effect on sexual performance.

Despite this, Spanish fly is still somewhat infamous several decades later — though most people know little about it. We assume that’s why you’re here.

Below, we’ll explain:

  • What Spanish fly is

  • The risks of using Spanish fly and its potential sexual effects

  • Whether Spanish fly is worth using or should be avoided

Finally, we’ll share a few alternatives you may want to consider if you’re aiming to boost your sexual desire and performance.

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What Is Spanish Fly?

Spanish fly technically refers to two things: a type of green blister beetle (Lytta vesicatoria from the family Meloidae) and a toxic blistering agent the beetles produce called cantharidin.

Historically, the green blister beetle was used to treat warts and a skin condition called molluscum.

Cantharidin — the product isolated from these beetles for medicinal formulation — has long been used as a natural aphrodisiac. Several millennia ago, it was used by ancient Egyptians and Romans as a stimulant for orgies, improving sexual relationships and as a tool for committing sexual blackmail.

If sexual blackmail is what you’re here for and you’re wondering where to buy Spanish fly today, hold up a second. First, that’s wrong, and second, you’re in for a disappointment. 

In modern times, supplements marketed as “Spanish fly” may not even contain cantharidin. Instead, they might contain various herbal ingredients that — manufacturers claim — are capable of boosting sexual performance, stamina and attractiveness.

Does Spanish Fly Work?

When it comes to non-prescription aphrodisiacs and male enhancement pills, manufacturers are often big on promises but small on actual results. The evidence that Spanish fly works is, likewise, very slim and disappointing.

Purportedly its core ingredient, cantharidin, increases blood flow to the urogenital tract. But the fact is that most reliable research quickly dismisses cantharidin as dangerous for human consumption.

Put simply, authentic Spanish fly isn’t something you or your partner want to consume, no matter what potential you’ve read about. It’s a hazardous substance and cases of poisoning can happen in rare circumstances — which could have serious consequences.

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Risks and Side Effects of Spanish Fly

When it comes to products containing cantharidin (and not some other random ingredients), there are serious safety risks you should be aware of if you’re considering taking these types of herbal supplements.

The first very real risk, it turns out, is a little thing called dying. 

Cantharidin is listed in the Hazardous Substances Data Bank of the National Library of Medicine.

People have died from using products containing cantharidin. In England, two women were killed by a man who gave them coconut ice laced with ​​cantharidin, hoping it would lead to them having sex with him.

And people in the United States have been rushed to the emergency room after taking cantharidin in the hope of stimulating sexual activity.

Assuming you don’t die, side effects associated with cantharidin you might experience include:

  • Blistering. Cantharidin is known to cause skin blisters. You may notice skin blisters, a burning sensation, itching and changes in pigmentation after you use products containing cantharidin.

  • Blood in saliva, vomit or urine. Cantharidin is known to cause hematemesis (vomiting of blood) and gross hematuria (blood visible in urine). It can also cause dysuria (pain while urinating).

  • Priapism. Cantharidin can cause priapism — a type of painful, long-lasting erection that can damage your penis when left untreated. Priapism is a serious medical emergency that requires urgent attention from a healthcare provider.

Cantharidin poisoning can also cause:

  • Seizures

  • Burning of the mouth

  • Renal dysfunction

  • Cardiac abnormalities

  • Nausea and dysphagia (difficulty swallowing)

There’s one final risk of Spanish fly to consider: the mystery ingredient trap. Products labeled “Spanish fly” aren’t regulated by the FDA (U.S. Food and Drug Administration) in the same way that prescription medications are, so there’s no real way to know what’s in them. The FDA maintains a long list of other sexual performance booster supplements that have been found to contain unlabeled, potentially dangerous ingredients. 

In other words, you can’t always be sure you’re getting the right amount of cantharidin — or what else you’re getting along with it — from non-prescription sexual enhancement products. And regardless of whether you get any cantharidin, you could potentially die.

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Better Options for Boosting Sexual Performance 

Spanish fly — any fly of any nationality, really — probably isn’t where you want to look for ED help. 

Natural cures are great — in theory. But if we’re being honest, most aren’t practical because we don’t know all of the facts or understand safe and effective dosages.

If we were to tell you cat poop is a natural ED (erectile dysfunction) treatment but that it wasn’t clear how much of it you needed to consume, we hope that information would lead you to visit a doctor — not a pet store.

While Spanish fly is proven to be neither safe nor effective as an aphrodisiac, there are real options available for treating sexual dysfunction and improving your performance in bed. 

Some of these require a prescription, while others are available online and over the counter, including:

  • ED medications

  • PE medications

  • Lifestyle changes

Let’s look at each group in more detail.

Erectile Dysfunction (ED) Medications

If you're thinking about using Spanish fly for ED, we get where you’re coming from, even if your plan is bad.

After all, erectile dysfunction is pretty common — it’s estimated to affect approximately 30 million men in the U.S. alone.

But there are safer, scientifically proven options to consider. Currently, the FDA has approved four pills for treating erectile dysfunction:

These all belong to a class of medications referred to as PDE5 inhibitors. They work by increasing blood flow to your penis, making it easier to get and maintain an erection when you feel sexually aroused.

The FDA has also approved an injectable medication, alprostadil, for ED, and it has authorized a topical gel for ED.

We offer several oral ED medications online, following a consultation with a healthcare provider who’ll determine if a prescription is appropriate.

Premature Ejaculation (PE) Medications

Like ED, premature ejaculation (PE) is a common sexual performance issue that can cause serious harm to your confidence and sexual pleasure. 

Premature ejaculation is very treatable. If you’re prone to PE, you’ll get the best results by using medication to slow down orgasm and ejaculation. Your options include:

  • Antidepressants. Some antidepressants, including sertraline (Zoloft®) and paroxetine (Paxil®) are used off-label to treat PE. Research shows that these medications help slow down ejaculation and improve stamina for men with PE.

  • ED medications. Off-label usage of ED medications, such as sildenafil (Viagra®) can also be effective for PE.

  • Topical PE products. It’s also possible to treat premature ejaculation topically. Products like our Delay Spray for Men are designed to reduce sensitivity, allowing you to have sex for longer before reaching orgasm. 

Lifestyle Changes for Better Sexual Function

While medication may provide the fastest effects, you’ll get the best results by combining it with a healthy lifestyle. 

Try the following habits and lifestyle changes to improve your physical health and sexual function:

  • Stay physically active. Regular exercise can have a hugely positive impact on your physical health, sexual performance and erectile function. Try to get 150 minutes or more of moderate-intensity aerobic exercise per week, as well as a couple of strength workouts per week.

  • Maintain a healthy body weight. Research has found that having overweight or obesity is linked to a higher risk of experiencing ED. Try to maintain a BMI either within or as close to the healthy range as possible.

  • If you smoke, try to quit. Research shows that smoking is linked to an increased risk of developing sexual performance issues, including ED. It’s also a key risk factor for other medical conditions, including potentially fatal ones, such as cancer and heart disease. If you smoke, try your hardest to quit.  

  • Live a healthy, balanced lifestyle. From sleep to diet, a variety of factors can affect your sexual performance. Our guide to naturally protecting your erections shares tactics you can use to live a life that prioritizes your sexual health and function.

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Why Spanish Fly Pills Aren’t Worth It

Spanish fly isn’t just ineffective as an aphrodisiac — it’s also dangerous. We’ve said it a dozen times already, but we’ll keep saying it! Why? Because dying is bad.

So keep Spanish fly and other herbal aphrodisiacs at arm’s length. There’s just way too much at stake.

Here’s our take on Spanish fly:

  • By using it to increase your sex drive, you’re putting your health at risk. 

  • Don’t give it to other people in an effort to make them feel more attracted to you.

  • Giving it to someone else without their permission is both unsafe and illegal.

  • Why would you do that? 

  • Don’t be that guy.

If you need help with your sexual performance, you can view our range of ED treatments online and connect with a licensed healthcare provider to discuss your needs. 

And here’s one final piece of free advice: instead of setting the mood with a European beetle roofie, do it by enjoying a romantic dinner or a glass of wine with your partner — not only is it more effective, but it’s also better for your health and theirs.

12 Sources

  1. Prischmann, D.A. & Sheppard, C.A. (2002, Winter). A world view of insects as aphrodisiacs, with special reference to Spanish fly. American Entomologist. Retrieved from https://booksc.eu/book/44094666/19403c
  2. PubChem Compound Summary for CID 5944, Cantharidin. (2021). Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/5944
  3. Cantharidine. (2021). Retrieved from https://pubchem.ncbi.nlm.nih.gov/source/hsdb/2181
  4. Karras, D.J., Farrell, S.E., Harrigan, R.A., Henretig, F.M. & Gealt, L. (1996, September). Poisoning from "Spanish fly" (cantharidin). American Journal of Emergency Medicine. 14 (5), 478-83. Retrieved from https://pubmed.ncbi.nlm.nih.gov/8765116/
  5. Ogilvie-Turner, K. & Goldman, R.D. (2020, June). Cantharidin for molluscum contagiosum. Canadian Family Physician. 66 (6), 419–420. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7292508/
  6. Karras, D.J., et al. (1996, September). Poisoning from “Spanish fly” (cantharidin). The American Journal of Emergency Medicine. 14 (5), 478-483. Retrieved from https://www.sciencedirect.com/science/article/abs/pii/S0735675796901588
  7. Moed, L., Shwayder, T.A. & Chang, M.W. (2001). Cantharidin Revisited A Blistering Defense of an Ancient Medicine. Archives of Dermatology. 137 (10), 1357-1360. Retrieved from https://jamanetwork.com/journals/jamadermatology/fullarticle/478535
  8. Tainted Sexual Enhancement Products. (2021, August 18). Retrieved from https://www.fda.gov/drugs/medication-health-fraud/tainted-sexual-enhancement-products
  9. Definition & Facts for Erectile Dysfunction. (2017, July). Retrieved from https://www.niddk.nih.gov/health-information/urologic-diseases/erectile-dysfunction/definition-facts
  10. Esposito, K., et al. (2008, April 10). Obesity and sexual dysfunction, male and female. International Journal of Impotence Research. 20, 358-365. Retrieved from https://www.nature.com/articles/ijir20089
  11. Kovac, J.R., Labbate, C., Ramasamy, R., Tang, D. & Lipshultz, L.I. (2015, December). Effects of cigarette smoking on erectile dysfunction. Andrologia. 47 (10), 1087–1092. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4485976/
  12. Lee, J. K., Tan, R. B., & Chung, E. (2017). Erectile dysfunction treatment and traditional medicine-can East and West medicine coexist?. Translational andrology and urology, 6(1), 91–100. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5313309/.
Editorial Standards

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references. See a mistake? Let us know at [email protected]!

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.

Mike Bohl, MD, MPH, ALM

Dr. Mike Bohl is a licensed physician and the Director of Scientific & Medical Content at a stealth biotech startup. Prior to joining Hims & Hers, Dr. Bohl spent several years in digital health focusing on patient education. He has also worked in medical journalism for The Dr. Oz Show and Sharecare and has served on the Medical Expert Board of Eat This, Not That!.

Dr. Bohl obtained his Bachelor of Arts and Doctor of Medicine from Brown University, his Master of Public Health from Columbia University, and his Master of Liberal Arts in Extension Studies—Journalism from Harvard University. He is currently pursuing a Master of Business Administration and Master of Science in Healthcare Leadership at Cornell University. Dr. Bohl trained in internal medicine with a focus on community health at NYU Langone Health.

Dr. Bohl is Certified in Public Health by the National Board of Public Health Examiners, Medical Writer Certified by the American Medical Writers Association, a certified Editor in the Life Sciences by the Board of Editors in the Life Sciences, a Certified Personal Trainer and Certified Nutrition Coach by the National Academy of Sports Medicine, and a Board Certified Medical Affairs Specialist by the Accreditation Council for Medical Affairs.

In addition to his written work, Dr. Bohl has experience creating medical segments for radio and producing patient education videos. You can find Dr. Bohl on LinkedIn for more information

Dr. Bohl lives in Manhattan and enjoys biking, resistance training, sailing, scuba diving, skiing, tennis, and traveling. You can find Dr. Bohl on LinkedIn for more information.

Education

  • Bachelor of Arts, Egyptian and Ancient Western Asian Archaeology. Brown University |

  • Doctor of Medicine. |

  • Master of Public Health, General Public Health. |

  • Master of Liberal Arts, Journalism. |

  • Master of Business Administration. | (anticipated 2024)

  • Master of Science, Healthcare Leadership. | (anticipated 2024)

Training

  • NYU Internal Medicine Residency—Brooklyn Community Health Track. |

Certifications

  • Certified in Public Health.

  • Medical Writer Certified.

  • Editor in the Life Sciences.

  • Certified Personal Trainer.

  • Certified Nutrition Coach.

  • Board Certified Medical Affairs Specialist. Accreditation Council for Medical Affairs

  • Digital Storytelling Graduate Certificate.

  • Marketing Management and Digital Strategy Graduate Certificate.

Publications

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