How long does it take for Senna to work?
- Senna takes around 6 to 12 hours to work (but usually about 8 hours), so it’s better to take it at night before bed.
- When taken rectally, it can take as little as 10 minutes to work.
- Senna tea starts working around 1 to 3 hours after taking it.
Can you use Senna for Bloating relief?
Senna herbal tea is used as a natural, over the counter laxative to help with bloating, constipation, gas, bowel detox, and weight loss.
Should you take Senna at night?
If you take Senna at night (before bed), it will work 6 to 8 hours later making bowel movements easier to pass when you wake up the next morning.
The video below shows how Senna can help with constipation.
This is our recommended Senna Alexandrina supplement (Amazon’s Choice):
Below you will find the results of 6 studies about Senna for constipation:
- Title: A volunteer model for the comparison of laxatives in opioid-related constipation.
- Number of Subjects: 10.
- Health Status: opioid-induced constipation in healthy volunteers.
Each volunteer took a sequence of three dose levels of loperamide. One of three laxatives was used to counterbalance the effect of loperamide and restore bowel function to what the individual considered normal at each stage before the dose of loperamide was increased.
Lactulose, senna, and codanthrusate were selected as examples of a softening, a stimulant, and a combination laxative, respectively.
Outcome measures were the doses of laxative used, stool form and frequency, ease of defecation, a rating scale of subjective bowel function, and the occurrence of adverse effects.
Each laxative was taken by ten volunteers, and all proved capable of maintaining normal bowel function. A combination of stimulant and softening laxatives was most likely to maintain normal bowel function at the lowest dose and least adverse effects. The mean final dose of lactulose was excessive for use in ill patients.
Senna was associated with significantly more adverse effects than the other laxatives, mainly abdominal pain.
This model of constipation may provide a standardized means of assaying the clinical effectiveness of oral laxatives.
- Title: Comparison of the effect of drugs upon some commonly used measures of bowel transit time.
- Number of Subjects: 10.
- Health Status: normal health condition.
To study the effect of drugs to reduce gut transit time a study of the effect of single doses of placebo, oxyphenisatin, anthracenes, (+)-norpseudoephedrine and a combined preparation of (+)-norpseudophedrine and senna was carried out in ten normal volunteers. Gut transit time was assessed.
It was possible to demonstrate the effect of the anthracenes but not oxyphenisatin on gut transit time. More sophisticated techniques were required to demonstrate the retarding effect of the sympathomimetic amine and its reversal by senna.
Statistical analysis shows that assessment of intestinal transit time gives identical information.
- Title: Efficacy of senna versus lactulose in terminal cancer patients treated with opioids.
- Number of Subjects: 91.
- Health Status: terminal cancer patients with opiod treatment.
The best laxative for terminal cancer patients treated with opioids still remains to be determined. This comparative study was conducted with the objective of determining treatment and cost efficiency for senna and lactulose in terminal cancer patients treated with opioids. The study was conducted in the Palliative Care Unit in one Madrid Health Care District.
Ninety-one terminal cancer patients were randomized into two groups: A = treated with senna (starting with 0.4 mL daily), and B = treated with lactulose (starting with 15 mL daily) for a 27-day period. The main outcome measures were defecation-free intervals of 72 hr, days with defecation, general health status, and treatment cost. Laxative efficacy was analyzed.
No difference was found between the laxatives in defecation-free intervals or in days with defecation. The final scores for general health status were similar in both groups.
Given that the two treatments have similar efficacy and adverse effects, a recommendation is made for the use of senna because its cost is lower than lactulose.
- Title: Safety and efficacy of a bulk laxative containing senna versus lactulose in the treatment of chronic constipation in geriatric patients.
- Number of Subjects: 30.
- Health Status: chronic constipation.
- Age range: 65-94 years.
- Mean age: 81.8 years.
Thirty geriatric long-stay patients aged (mean 81.8) participated in the trial the aim of which was to examine bulk laxative plus senna (Agiolax) in the treatment of chronic constipation using lactulose (Levolac) as a reference medicine.
Bulk laxative plus senna (daily doses 14.8 g) produced more frequent (p < 0.05) bowel habits (4.5 vs. 2.2-1.9/week) than lactulose (daily doses 20.1 g). Both laxatives proved to be safe to use.
Our study indicated bulk laxative plus senna to be more efficient in treating constipation in geriatric long-stay patients.
- Title: Standardized senna in the management of constipation in the puerperium: A clinical trial.
- Health Status: postpartum.
- Gender: female.
Successful treatment of constipation in the immediate postpartum period in 93% of White patients and 96% of Coloured patients was achieved in a clinical trial of standardized senna tablets (Senokot; Reckitt & Colman). This is significantly better than the success rates of 51% and 59% achieved in White and Coloured controls treated with a placebo.
Minor abdominal cramps occurred in some 13% of the patients treated with standardized senna, and in 4% of the controls given the placebo. There is no evidence to suggest that standardized senna has any effect whatsoever on a breast-fed baby if taken by the mother.
- Title: The use of senna with docusate for postoperative constipation after pelvic reconstructive surgery: a randomized, double-blind, placebo-controlled trial.
- Length: 7 days.
- Number of Subjects: 96.
- Health Status: post surgery.
The objective of the study was to compare time to first bowel movement (BM) after surgery in subjects randomized to placebo or senna with docusate.
Ninety-six subjects completed a baseline 7-day bowel diary before and after surgery. After pelvic reconstructive surgery, the subjects were randomized to either placebo (45 patients) or senna (8.6 mg) with docusate (50 mg) (48 patients). Time to first BM and postoperative use of magnesium citrate were compared.
There was a significant difference in the time to first BM in those receiving senna with docusate vs placebo. More subjects in the placebo group needed to use magnesium citrate to initiate a bowel movement.
The use of senna with docusate decreases time to first BM in those undergoing pelvic reconstructive surgery compared with placebo. Subjects using senna with docusate are also significantly less likely to use magnesium citrate.
Want to know more?
Click the links below to access the individual topic pages:
This article makes use of information from the U.S. National Library of Medicine under the terms of the Creative Commons Attribution 4.0 International License.
- Sykes NP. A volunteer model for the comparison of laxatives in opioid-related constipation. J Pain Symptom Manage. 1996;11(6):363-369. doi:10.1016/0885-3924(96)00011-5
- Rogers HJ, House FR, Morrison PJ, Bradbrook ID. Comparison of the effect of drugs upon some commonly used measures of bowel transit time. Br J Clin Pharmacol. 1978;6(6):493-497. doi:10.1111/j.1365-2125.1978.tb00872.x
- Agra Y, Sacristán A, González M, Ferrari M, Portugués A, Calvo MJ. Efficacy of senna versus lactulose in terminal cancer patients treated with opioids. J Pain Symptom Manage. 1998;15(1):1-7. doi:10.1016/S0885-3924(97)00276-5
- Kinnunen O, Winblad I, Koistinen P, Salokannel J. Safety and efficacy of a bulk laxative containing senna versus lactulose in the treatment of chronic constipation in geriatric patients. Pharmacology. 1993;47 Suppl 1:253-255. doi:10.1159/000139866
- Shelton MG. Standardized senna in the management of constipation in the puerperium: A clinical trial. S Afr Med J. 1980;57(3):78-80.
- Patel M, Schimpf MO, O’Sullivan DM, LaSala CA. The use of senna with docusate for postoperative constipation after pelvic reconstructive surgery: a randomized, double-blind, placebo-controlled trial. Am J Obstet Gynecol. 2010;202(5):479.e1-479.e4795. doi:10.1016/j.ajog.2010.01.003