Skip to Content
View Additional Content In This Section
Injections of botulinum toxin (Botox) may help heal a tear
(fissure) in the
The internal anal sphincter, one of
two muscles that control the anus, is always under tension. If this tension
(also called resting pressure) is too high, spasms and reduced blood flow can
cause an anal fissure or prevent an existing one from healing. Botulinum toxin,
the poison that causes
botulism, temporarily paralyzes the internal anal
sphincter. This reduces the spasm and allows the fissure to heal.
Botulinum injections may be more helpful than nitroglycerin ointment, but
the studies do not all agree.footnote 1, footnote 2 A review of many studies showed that injections of botulinum
toxin were no better at healing anal fissure than nitroglycerin
ointment.footnote 3 Fissures may return after treatment with
Botox is discontinued.
Side effects of botulinum injections may
include the inability to control the passage of gas (gas incontinence), pain
from the injections, bleeding, infection at the injection site, and
fecal incontinence. Most people do not have any side
Botulinum toxin injections can
Fruehauf H, et al. (2006). Efficacy and safety of botulinum toxin A injection compared with topical nitroglycerin ointment for the treatment of chronic anal fissure: A prospective randomized study. American Journal of Gastroenterology, 101(9): 2107–2112.
Brisinda G, et al. (2007). Randomized clinical trial comparing botulinum toxin injections with 0.2 per cent nitroglycerin ointment for chronic anal fissure. British Journal of Surgery, 94(2): 162–167.
Nelson R (2006). Non-surgical therapy for anal fissure. Cochrane Database of Systematic Reviews (4).
ByHealthwise StaffPrimary Medical ReviewerAnne C. Poinier, MD - Internal MedicineSpecialist Medical ReviewerC. Dale Mercer, MD, FRCSC, FACS - General Surgery
Current as ofNovember 14, 2014
Current as of:
November 14, 2014
Anne C. Poinier, MD - Internal Medicine & C. Dale Mercer, MD, FRCSC, FACS - General Surgery
To learn more about Healthwise, visit Healthwise.org.
© 1995-2015 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.