The short answer. There isn't much data on Lactulose yet — 3 mentions, 1 with a clear outcome — so treat these numbers as anecdotal. It is well studied — 130 meta-analyses on PubMed.
From 3 mentions in total — the rest didn't say how it went and aren't counted.
Of the people who reported each effect, the share who said it got better.
Systematic reviews and meta-analyses from PubMed, with their published conclusions.
3+ meta-analyses or systematic reviews and 10+ randomized controlled trials in humans. The grade measures how much human research exists — read the conclusions below for what it found.
Conclusion: Regarding T-cell lymphocytes, a slight decrease was observed, although it failed to reach significance (MD: -0.16, 95% CI: -0.33, 0.01, p = 0.07). Conclusion: The wound healing might be enhanced in one or at various stages by nutritional supplementation in the right dose.
PubMed 34444657 ↗Conclusion: Moreover, the use of rifaximin plus lactulose was associated with a reduced risk of mortality as compared with lactulose alone (RR, 0.57; 95% CI, 0.41-0.80; P = 0.001). This study found that the use of rifaximin in combination with lactulose could provide additional benefits in terms of increased effective rate and decreased mortality than lactulose alone in patients with HE.
PubMed 35471992 ↗Conclusion: Polyethylene Glycol should be used in preference to Lactulose in the treatment of Chronic Constipation.
PubMed 20614462 ↗Conclusion: Polyethylene glycol is probably more effective than placebo and key comparator therapies and should be considered the standard of first-line care. Future studies should consider polyethylene glycol as an index therapy, and clearly describe methods, patient characteristics, and previous therapeutics.
PubMed 41101321 ↗How often each side effect came up across all reports.
First-hand experiences, quoted verbatim. We show one positive and one negative where both exist.
User data from public discussions; research from PubMed. Information only, not medical advice — talk to a doctor before starting, stopping or combining anything. Data updated October 3, 2026. How we rate