Grapefruit Seed
Also known as citricidal, grapefruit extract, grapefruit seed, grapefruit seed extract
Key takeaways
- GSE acts as a natural antibacterial substance against multidrug-resistant bacteria (PMID: 33477436).
- GSE is effective in preventing Pseudomonas spp. contamination in edible mushrooms (PMID: 38672835).
- GSE can be incorporated into composite films to provide antibacterial properties for food packaging (PMID: 30189274).
What the research shows
AI-synthesized from 7 peer-reviewed sources · Updated 2025
Grapefruit Seed Extract (GSE) is primarily researched as a natural antimicrobial agent. Current evidence focuses heavily on its efficacy in food preservation and its antibacterial properties against various pathogens, though clinical human data is limited.
By condition
Antimicrobial/Antibacterial Activity
Moderate
GSE demonstrates significant antibacterial activity against a variety of bacteria, including multidrug-resistant strains and food-borne contaminants.
Effective doses
No human RCT dose ranges provided in the sources.
Safety & interactions
Artificial grapefruit seed extract products have been associated with adverse effects in patients undergoing warfarin therapy (PMID: 17468864).
Limitations
The majority of the research is conducted in vitro or in food-science applications rather than in human clinical trials. There is a lack of evidence regarding therapeutic efficacy for internal human health conditions.
Top-rated Grapefruit Seed products
Ranked by safety score and evidence coverage
How it's sold
Data aggregated from 74 product labels
Research evidence
Showing top 10 of 7 sources, sorted by quality
**Choi et al., 2014** | J Food Sci | Other Choi Jae-Suk, Lee Yu-Ri, ... Sohn Jae Hak. Antibacterial effect of grapefruit seed extract (GSE) on Makgeolli-brewing microorganisms and its application in the preservation of fresh Makgeolli. J Fo…
**Murgia et al., 2024** | Foods | Other Murgia Marcello, Pani Sara Maria, ... Coroneo Valentina. Antimicrobial Activity of Grapefruit Seed Extract on Edible Mushrooms Contaminations: Efficacy in Preventing Pseudomonas spp. in Pleurotus eryn…
**Kim et al., 2024** | Int J Food Microbiol | Other Kim Unji, Oh Se-Wook. Antimicrobial resistance induction potential of grapefruit seed extract on multi-species biofilm of E. coli in food industry. Int J Food Microbiol. 2024-Nov-02;424:11…
**Han et al., 2021** | Antibiotics (Basel) | Other Han Hee-Won, Kwak Jin-Hwan, ... Lee Jung-Hwan. Grapefruit Seed Extract as a Natural Derived Antibacterial Substance against Multidrug-Resistant Bacteria. Antibiotics (Basel). 2021-Jan-18;10…
**Shankar et al., 2018** | Int J Biol Macromol | Other Shankar Shiv, Rhim Jong-Whan. Preparation of antibacterial poly(lactide)/poly(butylene adipate-co-terephthalate) composite films incorporated with grapefruit seed extract. Int J Biol Ma…
**Brandin et al., 2007** | Eur J Clin Pharmacol | Other Brandin Helena, Myrberg Olle, ... Brenning Gunilla. Adverse effects by artificial grapefruit seed extract products in patients on warfarin therapy. Eur J Clin Pharmacol. 2007-Jun;63(6)…
**Semprini et al., 2004** | Vet Ital | Other Semprini P, Langella V, ... Calvarese S. Antibacterial properties of grapefruit seed extract against Paenibacillus larvae subsp. larvae. Vet Ital. 2004;40(2):39-45 Twenty-one samples of grapefrui…
Frequently asked questions
What is Grapefruit Seed Extract and what is it used for?
Grapefruit Seed Extract (GSE) is primarily researched as a natural antimicrobial agent with moderate evidence supporting its antibacterial activity against various pathogens, including multidrug-resistant strains. Current research focuses heavily on its efficacy in food preservation and packaging rather than clinical human health applications.
Does Grapefruit Seed Extract work for bacterial infections?
Research shows moderate evidence that GSE has significant antibacterial properties against various bacteria, including multidrug-resistant strains. However, clinical human data is limited, so it should not be used to replace prescribed medication for treating infections.
What is the effective dose of Grapefruit Seed Extract?
There are no human randomized controlled trial (RCT) dose ranges provided in the current evidence sources. Because effective dosing for humans is not established, you should consult a healthcare provider before using this supplement.
Is Grapefruit Seed Extract safe to take with warfarin?
Artificial grapefruit seed extract products have been associated with adverse effects in patients undergoing warfarin therapy, so it is not considered safe for this group. You should avoid this supplement if you are on blood thinners and consult your doctor first.
What are the side effects of Grapefruit Seed Extract?
While specific side effects are not detailed, artificial versions of this extract have been linked to adverse effects, particularly in patients taking warfarin. Evidence regarding safety in healthy individuals is limited, so caution is advised.
Who should avoid taking Grapefruit Seed Extract?
Patients undergoing warfarin therapy should avoid this supplement due to documented adverse effects. Additionally, because clinical human data is limited, pregnant or breastfeeding women and those on other medications should consult a healthcare provider before use.
Does Grapefruit Seed Extract interact with other drugs?
While no general drug interactions are documented in the summary, specific adverse effects have been noted for patients on warfarin therapy. It is essential to consult a healthcare provider to assess potential risks with your specific medication regimen.