Yohimbine is an indole alkaloid (found in Pausinystalia yohimbe and Rauwolfia serpentina) explored for its varied effects as a central nervous system (CNS) stimulant, anorectic and thermogenic agent, pro-erectogenic properties, and possible aphrodisiac properties. Yohimbine is active at the alpha-2A adrenergic receptor and increases resting energy expenditure. In various preliminary studies yohimbine has been shown to decrease sexual refractory period, reduce sexual exhaustion, reduce sexual satiety, increase semen ejaculation volume, and aid in treatment of anorgasmia. Yohimbine is also used in some experimental models to simulate anxiety and depression for research purposes, and to induce recall of traumatic memories in experimental treatment of post-traumatic stress disorder (PTSD).
According to the National Institutes of Health (NIH), yohimbine is an effective drug when prescribed for erectile dysfunction.  However, some studies suggest that it is not effective in more severe cases, and have found that the reported increase in libido (as opposed to potency) is anecdotal Morales et al state that "conflicting results available may be attributed to differences in drug design, patient selection, and definitions of positive response." 
 Rosengren AH, Jokubka R, Tojjar D, Granhall C, Hansson O, Li DQ, Nagaraj V, Reinbothe TM, Tuncel J, Eliasson L, Groop L, Rorsman P, Salehi A, Lyssenko V, Luthman H, Renström E. Overexpression of alpha2A-adrenergic receptors contributes to type 2 diabetes. Science. 2010 Jan 8;327(5962):217-20. Epub 2009 Nov 19.
 Kucio C, Jonderko K, Piskorska D. Does yohimbine act as a slimming drug? Isr J Med Sci. 1991 Oct;27(10):550-6.
 Fernández-Guasti A, Rodríguez-Manzo G (July 2003). "Pharmacological and physiological aspects of sexual exhaustion in male rats". Scandinavian Journal of Psychology 44 (3): 257–63.
 Yonezawa A, Yoshizumii M, Ebiko M, Amano T, Kimura Y, Sakurada S (October 2005). "Long-lasting effects of yohimbine on the ejaculatory function in male dogs". Biomedical Research 26 (5): 201–6.
 Adeniyi AA, Brindley GS, Pryor JP, Ralph DJ (May 2007). "Yohimbine in the treatment of orgasmic dysfunction". Asian Journal of Andrology 9 (3): 403–7.
 Dhir A, Kulkarni SK. Effect of addition of yohimbine (alpha-2-receptor antagonist) to the antidepressant activity of fluoxetine or venlafaxine in the mouse forced swim test. Pharmacology. 2007;80(4):239-43. Epub 2007 Jul 6.
 van der Kolk, Bessel A. (1995). "The Treatment of Post Traumatic Stress Disorder". in Hobfoll, Stevan E.; De Vries, Marten W.. Extreme stress and communities: impact and intervention. Boston: Kluwer Academic Publishers. pp. 421–44. ISBN 978-0-7923-3468-2.
 National Institutes of Health: Medline Plus. "Yohimbe bark extract (Pausinystalia yohimbe Pierre ex Beille Rubiaceae)" http://www.nlm.nih.gov/medlineplus/druginfo/natural/patient-yohimbe.html
 National Institutes of Health: National Center for Complementary and Alternative Medicine. "Herbs at a Glance: Yohimbe." http://nccam.nih.gov/health/yohimbe/
 Andersson KE (September 2001). "Pharmacology of penile erection". Pharmacological Reviews 53 (3): 417–50.
Andersson, Karl-Erik; Steers, William D. (1998). "The pharmacological basis of sexual therapeutics". in Morales, Alvaro. Erectile dysfunction: issues in current pharmacotherapy. London: Martin Dunitz. pp. 97–124 .