Celebrities are known to be on the cutting edge of strange and controversial treatments and products, from Kim Kardashian's blood facials, to Oprah's "foreskin face cream", and even Eva Longoria's placenta beauty secret.

One of the latest curiosities is cupping therapy. Last week, Jennifer Aniston arrived at the premiere of her new movie 'Call Me Crazy' in a strapless black dress that revealed circular marks on her back — widely speculated to be left behind by cupping, a Chinese medicine treatment.

Apparently Aniston is a devotee of the treatment and has been receiving it for years. A few years ago, alternative medicine fan Gwyneth Paltrow also arrived at a Hollywood premiere with visible cupping marks on her back, with no attempts to cover them up. She told Oprah about the treatment, saying "It feels amazing and it’s very relaxing, and it feels terrific."

So what exactly is cupping and why are stars embracing it?

Cupping is an ancient Chinese treatment that claims to relieve pain, cut stress, and up energy, among other effects, by increasing blood flow. In the treatment, heated glass cups are placed on the skin, which creates a suctioning effect that is meant to increase blood flow.

The milleniums­old treatment is based on the same principles as acupuncture, and the suctioning effect of the cups is meant to get blood and energy flowing in order to counteract what Chinese medicine practitioners refer to as stagnation. Cupping is meant to get the body's forces moving in order to promote healing in the affected area. The treatment can leave marks or bruises because of the suction, but they fade over time.

Celebrity fans of cupping include actors like Paltrow and Aniston and singers like Jessica Simpson and Lady Gaga, as well as Victoria Beckham, who was seen with cupping marks on her back in 2010. But the treatment is also favoured by tennis ace Andy Murray, who has said that he used cupping as part of an approach to relieve stiffness and a back injury. His longtime girlfriend Kim Sears seems less enthusiastic; she said in 2009 that the marks left behind by the treatment made him look "like a reptile."

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  • Breast Milk Soap

    Milk does do a body good. But the <a href="http://shine.yahoo.com/healthy-living/breast-milk-soap-it-does-a-body-good-2210353.html" target="_hplink">trend toward making your own soap</a> -- to be used when you shower or simply wash your hands -- out of breast milk is, well, a bit extreme. The trend emerged as people started to worry that brand-name soaps were full of chemicals and detergents that would harm their skin (or worse, cause cancer). And since milk is supposed to nourish the epidermis, well, why not turn excess breast milk into something, ahem, usable?

  • Solid Gold Facial

    Why not add a little bling to your beauty routine? Now you can -- if you live in Florida and have enough cash to dish out for the, wait for it, 24 carat gold facial. Yep! Mar-a-Lago in Palm Beach offers spa patrons the opportunity to have their entire body painted in gold. The thought is karats can help stave off cellulite and prevent aging.

  • Snake Venom Cream

    Just because Gwyneth Paltrow swears by this cream -- and its accompanying facial -- doesn't mean you should actually try applying <a href="http://www.refinery29.com/gwyneth-paltrow-snake-venom-anti-aging-treatment" target="_hplink">snake venom cream</a> to your face. Apparently, using a cream which has venom as an active ingredient helps plump up the skin (much in the same way botox does).

  • Bull Semen Hair Mask

    <a href="http://www.metro.co.uk/news/35685-new-hair-product-uses-bull-semen" target="_hplink">According to Metro.co.uk, a hairdresser, Hari's, in Knightsbridge, London, "has combined... organically produced [bull] semen with the root of protein-rich plant katera</a>," to make an intense hair conditioning treatment. The procedure apparently takes 45 minutes and costs over $100.

  • Fish Pedicures

    <a href="http://www.thestar.com/living/article/830236--little-nibblers-fish-pedicures-are-popular-but-controversial" target="_hplink">This popular treatment has become a spa go-to for women around the world who want softer, smoother feet</a>. Essentially, this treatment involves dipping your feet into a tank and letting hungry little fish -- Garra rufa fish -- gently eat away at the dead skin cells that make your skin feel rough. Some places and states have banned the practice for fears it may be unsanitary.

  • Fire Cupping

    Fire cupping is a natural treatment where a practitioner ignites a cotton ball soaked in alcohol and places it inside a cup. When the cup is placed against a patient's skin, a suction action begins to happen -- which is said to increase circulation. Once "activated," the glass bulbs can be moved to key "energy" points all over the body to boost the immune system and increase blood flow (which will help give skin a natural glow, making patients look younger). <a href="http://www.cbsnews.com/2100-500165_162-628788.html" target="_hplink">A big fan of the procedure is reportedly Gwyneth Paltrow</a>.

  • Beer Bath

    Who doesn't love a good soak in a tub? But one containing beer? Now that's interesting. All across Eastern Europe, people are "sudsing it up" in big tubs full of beer. The thinking is the hops and yeast are full of vitamins that will enrich skin with vitamins, exfoliate dead skin cells and help pores sweat out toxins. <a href="http://travel.nytimes.com/2006/04/30/travel/30surfacing.html" target="_hplink">Here's how you can explore the beauty treatment trend yourself</a>.

  • Bird Poo Or Placenta Facials

    We almost can't bring ourselves to write about these beauty trends, but they're too weird not to discuss. <a href="http://articles.cnn.com/2008-09-26/living/bird.poop.facials_1_facials-placenta-skin?_s=PM:LIVING" target="_hplink">In L.A., placenta facials -- which use placentas from Russian maternity wards -- are used on clients to nourish skin and prevent aging</a>. And many celebs, including Victoria Beckham, hail the "nightingale poo facial" as their biggest beauty saviour. <a href="http://www.dailymail.co.uk/femail/beauty/article-1350741/Its-hailed-beauty-wonder-product-Victoria-Beckham-loves--bird-poo-face.html#ixzz1qQrjRLaU" target="_hplink">According to the DailyMail</a>: "The nightingale poo acts as an exfoliate that brings out the dirt and dust that builds up in the skin and leaves the customer feeling refreshed."

  • Chocolate Body Wraps

    A chocolate body wrap? Well sign us up. Sure, there's no scientific evidence to support the claims treating your body to some of the sweet stuff will soothe, smooth and detoxify your skin, but it involves sitting in chococlate for an hour. Sounds pretty tasty to us. <a href="http://www.chocolatespa.com/" target="_hplink">Check out the spa devoted to all sorts of chocolatey good beauty treatments</a>.

  • Urine Therapy

    When we first heard that this weird beauty treatment may well be on the rise again, we had to do a bit of research. And here's what we found out: urine therapy was historically used by the Greeks and Romans to cure all that ailed them. It was also used to, ahem, whiten their teeth. Essentially, the procedure involves drinking your own urine in the hopes you'll look and feel younger. In modern times -- and on shows like '<a href="http://www.huffingtonpost.com/2012/03/19/my-strange-addiction-finale-drink-bathe-urine-pee-video_n_1360973.html" target="_hplink">My Strange Addiction</a>' -- people have been known to drink urine for various reasons. <a href="http://urinetherapy.tribe.net/thread/f604954c-4b97-4a1d-800f-39a03e41d87f" target="_hplink">Some scientists have even speculated urine has anti-carcinogenic properties</a> -- which could stave off cancer and wrinkles. <a href="http://www.medicinenet.com/urine_therapy/views.htm" target="_hplink">No real evidence has been found to support those claims</a>.