Supplements and Diazepam.
Diazepam, sold under the brand name Valium, is a benzodiazepine: it potentiates GABA at the GABA-A receptor.
Below are the 5 documented pairs we have explicitly assessed against Diazepam in the Distil database: 1 red and 4 amber. The pairs cluster around 2 mechanisms: Additive CNS depression and CYP3A4 induction. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not on this list is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by supplement, and the missing-item form at the bottom of the page routes any uncatalogued supplement into our next curation pass.
Documented interactions
Additive CNS depression
Kava and diazepam both depress the central nervous system through overlapping pathways, and kava is independently linked to liver injury. Combining the two raises the risk of excessive sedation and adds to the liver-injury risk that already exists with kava alone. We treat this as a do-not-combine pair.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Ashwagandha can have a mild sedating effect on top of its main anti-stress action. Combined with diazepam, the sedation can stack. Use with care around driving or heavy machinery.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Passionflower and diazepam both calm the nervous system through overlapping pathways. Combining them can mean stronger drowsiness and slower reactions. Akhondzadeh 2001 found passionflower comparable to oxazepam for generalised anxiety, which gives you a sense of the additive potential.
Valerian and diazepam both promote sedation through overlapping pathways. Combining them can mean stronger drowsiness, slower reaction time, and a heavier morning hangover than either gives on its own. Use with care, particularly around driving.
CYP3A4 induction
St John's Wort can speed up the breakdown of diazepam, which may mean it is less effective than expected at the prescribed dose. Talk to whoever prescribed it before combining.
What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope (food-supplement interactions only; for drug-drug interactions, the BNF is authoritative). Use the checker below to surface any supplement, and submit a missing item if you take something we have not catalogued.
For adults over 18.
This tool gives evidence-graded information, not medical advice. Always discuss changes with your GP, pharmacist, or specialist before making them, especially if you take any medication, are pregnant, breastfeeding, or have a serious health condition.
How we grade severity, choose what's in scope, and what we exclude.
Every call on this page is reasoned. We publish the full rubric for severity tiers, the medication inclusion logic, the evidence grades we accept, and what we deliberately leave out. About three thousand words. Worth reading once if you use this tool more than occasionally.
Read the full methodologySomething missing?
If a supplement or medication you take isn't in our autocomplete, tell us and we'll add it in the next quarterly update.