PlainPill

Ondansetron

The short answer. There isn't much data on Ondansetron yet — 4 mentions, 1 with a clear outcome — so treat these numbers as anecdotal. It is well studied — 204 meta-analyses on PubMed.

What users report
0%helped1 reports · few reports
0% helped25% mixed0% didn't

Out of 4 mentions; the other 75% didn't say how it went and aren't counted.

Clinical research
AStrong research base
204
meta-analyses
1,191
RCTs
5,480
papers

What Ondansetron does, according to users

Of the people who reported each effect, the share who said it got better.

No specific effects reported yet.
betterno changeworse

What the research says

Systematic reviews and meta-analyses from PubMed, with their published conclusions.

AStrong research base

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.

Cochrane Database Syst Rev · 2020 · Meta-analysis / systematic review
Drugs for preventing postoperative nausea and vomiting in adults after general anaesthesia: a network meta-analysis

Conclusion: We found high-certainty evidence that five single drugs (aprepitant, ramosetron, granisetron, dexamethasone, and ondansetron) reduce vomiting, and moderate-certainty evidence that two other single drugs (fosaprepitant and droperidol) probably reduce vomiting, compared to placebo. Four of the six substance classes (5-HT₃ receptor antagonists, D₂ receptor antagonists, NK₁ receptor antagonists, and corticosteroids) were thus represented by at least one drug with important benefit for prevention of vomiting. Combinations of drugs were generally more effective than the corresponding single drugs in

PubMed 33075160 ↗
Ann Emerg Med · 2025 · Meta-analysis / systematic review
Efficacy and Safety of Pharmacologic Therapies for Nausea and Emesis in the Emergency Department: A Systematic Review and Bayesian Network Meta-analysis

Conclusion: Within a minimally contextualized framework, as single agents, intravenous tropisetron and intravenous prochlorperazine are definitely among the most effective, intravenous metoclopramide and intravenous droperidol are possibly among the most effective, and oral ondansetron is definitely among the least effective; considering certain adverse reactions, intravenous metoclopramide, intravenous droperidol, and intravenous promethazine are definitely among the most harmful.

PubMed 40772912 ↗

Dosage people report

We don't list doses for prescription medications. Dosing should only come from a doctor or pharmacist.

Reported side effects

How often each side effect came up across all reports.

No side effects reported so far.

What users say

First-hand experiences, quoted verbatim. We show one positive and one negative where both exist.

More medications

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