Find and read the adverse events reported in a clinical trial
The adverse events section records the harms seen during a trial: what happened, how often, in which arm and how severe it was. The detail is often split between the main text, a harms table and an appendix. Ask Search+ "Which adverse events occurred more often in the treatment arm, and how were serious events defined?" and open the citations to read the report's own wording and figures.
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Last updated October 2026
How to find adverse event data with Search+
- Upload the report with its appendices
Harms tables are frequently in supplementary material. Add the report and any appendix files to the same workspace so an answer can reach the full table.
- Ask about each kind of event separately
Ask about all adverse events, serious adverse events, events leading to withdrawal and deaths as separate questions. Reports usually count each category differently, and separate questions keep each figure tied to its own citation.
- Check definitions and follow the table references
When an answer mentions a grading scale or a table, ask how the report defines the severity grades or what the table covers, and open the citation to read it directly.
Questions to ask about adverse events
How many participants in each arm had at least one adverse event?
How does the report define a serious adverse event, and how many occurred in each arm?
How many participants stopped treatment because of an adverse event, and which events were involved?
Which adverse events were most common in the treatment arm?
How and how often were adverse events collected during the trial?
What to look for in an adverse events section
An adverse event is any unfavorable medical occurrence during the trial, whether or not it was caused by the treatment. A reaction or treatment-related event is one judged to be linked to it. Check which term the report uses.
In trial reporting, a serious adverse event usually means one that is life-threatening, leads to hospitalization, disability or death, or meets similar criteria. It is about seriousness, not severity grade; read the definition the report gives.
Many trials grade severity with a published scale, and the report or protocol names it. Ask which scale was used before comparing grades.
Events may be counted only during treatment or for a set time after. Spontaneous reporting finds fewer events than systematic questioning, so the method affects the numbers.
Each answer cites the excerpt it used, with a page or section reference when the report provides one. Open it to read the number in its table or sentence.
Adverse event wording and what to ask next
| Wording you may see | What it usually signals | A follow-up question |
|---|---|---|
| "treatment-emergent adverse event" | An event that began or worsened after treatment started | From what point were treatment-emergent events counted? |
| "serious adverse event" | An event meeting seriousness criteria such as hospitalization | How many serious events occurred per arm? |
| "related" or "possibly related" | The investigator's judgment of a link to treatment | Who judged relatedness, and was it blinded? |
| "grade 3 or higher" | Severe events on a grading scale | Which grading scale did the trial use? |
| "discontinued due to adverse events" | Events that ended treatment | Which events most often led to discontinuation? |
| "no new safety signals" | The authors' summary judgment | What data does the report give to support that statement? |
What are adverse events in a clinical trial report?
Adverse events in a clinical trial report are the unfavorable medical occurrences recorded in participants during the trial, reported by type, frequency, seriousness and study arm, whether or not they were caused by the intervention.
Adverse event questions
Can Search+ list every adverse event in a trial report?
Can it tell me whether an event was caused by the drug?
Will it find serious adverse events listed in an appendix?
Is this safety advice about a medicine?
Can I compare adverse events across trials?
Could an answer get a number wrong?
Read the harms, not just the headline
Start a workspace, upload the report and its appendices, and ask what adverse events were recorded.
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