Boric acid

E number E284CAS 11113-50-1

Listed as a lubricant or release agent by the US.

Listed as lubricants and release agents (US)
Chemical structure of Boric acid, from PubChem compound 7628
Structure from PubChem CID 7628 (National Library of Medicine, public domain). A depiction of one compound: where a listing covers a family, or a substance has no single structure, this page shows none.

Boric acid is permitted in the EU as a preservative in exactly one food: sturgeon caviar. It was once a common preservative and was withdrawn from everything else; caviar is the exception.

Where it is and isn’t permitted

Status of Boric acid by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
JurisdictionStatusScope and limitsCitation
Australia and New ZealandFood Standards Australia New ZealandNo listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it.
CanadaHealth CanadaNo listing matchedHealth Canada’s lists name additives without E or INS numbers, so this site matches them by exact name. A substance listed there under a name this site does not recognise has no row here.
European UnionEuropean Commission / EFSAPermitted, with conditions

1 food category

highest permitted level 4,000 mg/kg

ML = 4000 mg/kg. only Sturgeons' eggs (Caviar). Note 54: Expressed as boric acid.

Regulation (EC) No 1333/2008, Annex II, as amended by (EU) No 1129/2011retrieved 2026-10-18
Great BritainFood Standards Agency / Food Standards ScotlandPermitted, with conditions

1 food category

highest permitted level 4,000 mg/kg or mg/l

ML = 4000. only Sturgeons’ eggs (Caviar). Note (54): Expressed as boric acid.

Assimilated Regulation (EC) No 1333/2008, Annex II (as at 28 June 2024)retrieved 2026-10-18
JapanConsumer Affairs AgencyNo listing matchedThis site imports only Japan’s list of designated additives (Appended Table 1 to the Regulations for Enforcement of the Food Sanitation Act), matched by English name. Existing additives, natural flavouring agents and ordinary foods used as additives are permitted outside that list and are not imported, so an empty row does not show that Japan does not permit the substance.
South KoreaMinistry of Food and Drug SafetyNo listing matchedThis site imports Part III of South Korea’s Standards and Specifications for Food Additives, matched by CAS number, then INS number, then exact name. Mixed preparations and sanitisers are not imported, and an entry whose identifiers disagreed with a page’s is held for review, so an empty row does not show that South Korea does not permit the substance.
United StatesFood and Drug AdministrationNot listedDoes not appear on this jurisdiction’s permitted list. That is not the same as being prohibited.
Codex AlimentariusCodex Alimentarius Commission / JECFANot listedDoes not appear on this jurisdiction’s permitted list. That is not the same as being prohibited.

How much is permitted

A listing usually limits the quantity as well as the food. Only one of the forms that takes is a figure: quantum satis and good manufacturing practice permit the amount the technological effect requires and no more, which is a limit rather than the absence of one. Figures below are the range across every food category this page is listed in, and categories differ between regulators — see how much is permitted.

European Union4,000 mg/kg1 numeric limit
Great Britain4,000 mg/kg1 numeric limit

What FDA’s inventory records

This page holds no listing for Boric acid in the parts of 21 CFR this site reads. FDA’s Substances Added to Food inventory does carry it, as BORIC ACID, pointing at a food-contact regulation, not a listing for use in food: 21 CFR 175.105, 21 CFR 176.180, 21 CFR 178.2010, 21 CFR 181.30.

Technical effects FDA records: lubricant or release agent.

The inventory is an information resource: a row means FDA holds information about the substance’s use in food, not that the substance is listed for that use. It is shown apart from the permissions above and is not counted as a US permission anywhere on this site.

What it is made from

Produced by treating borate minerals such as borax with sulfuric acid.

  • Vegan
  • Vegetarian

Compare other additives on the dietary indexes.

CAS registry number
11113-50-1
InChIKey
KGBXLFKZBHKPEV-UHFFFAOYSA-N
PubChem
CID 7628

How the EU defines it

The legal specification an additive must meet to be sold as this E number in the EU — what it is, how it may be made, and the purity it must reach. From Commission Regulation (EU) No 231/2012.

E 284 Boric acid

Synonyms: Boracic acid; Orthoboric acid; Borofax

Assay, identification and purity criteria

Description and assay

Einecs
233-139-2
Chemical formula
H₃BO₃
Molecular weight
61,84
Assay
Content not less than 99,5 %
Description
Colourless, odourless, transparent crystals or white granules or powder; slightly unctuous to the touch; occurs in nature as the mineral sassolite

Identification

Melting point
At approximately 171 °C
Burning test
Burns with a nice green flame
pH
3,8-4,8 (3,3 % aqueous solution)

Purity criteria

Peroxides
No colour develops with added KI-solution
Arsenic
Not more than 1 mg/kg
Lead
Not more than 5 mg/kg
Mercury
Not more than 1 mg/kg

Commission Regulation (EU) No 231/2012, Annex, E 284

Every name it appears under

84 recorded names. A label may use any of them.

E number

  • E284

CAS registry number

  • 10043-35-3
  • 11113-50-1

As it appears in regulation

  • Boric acid

Other names

  • (10B)Orthoboric acid
  • Acidum boricum
  • Ant flip
  • Basilit B
  • Bluboro
  • Bluboro (Salt/Mix)
  • Boracic acid
  • BORIC ACID
  • Boric acid (BH3O3)
  • Boric acid (h(sub 3)bo(sub 3))
  • Boric acid (H3BO3)
  • Boric acid (TN)
  • Boric acid (VAN)
  • Boric acid flakes
  • BORIC ACID, ACS
  • Boricum acidum
  • Borofax
  • Boron hydroxide
  • Boron trihydroxide
  • Borsaeure
  • Borsaure
  • Canagyn
  • Caswell No. 109
  • CCRIS 855
  • Collyrium Eye Wash
  • Dr.'s 1 Flea Terminator DF
  • Dr.'s 1 Flea Terminator DFPBO
  • Dr.'s 1 Flea Terminator DT
  • Dr.'s 1 Flea Terminator DTPBO
  • E 284
  • EPA Pesticide Chemical Code 011001
  • Flea Prufe
  • GYNOX-SOFT
  • Homberg's salt
  • Homeopathic Antifungal
  • HSDB 1432
  • hydrogen orthoborate
  • HYLAFEM
  • HYLAFEM BORICUM ACIDUM 3X
  • INS NO.284
  • INS-284
  • Kill-off
  • Kjel-sorb
  • Niban Granular Bait
  • Optibor
  • Orthboric Acid
  • ortho-boric acid
  • Orthoboric acid
  • Orthoboric acid (B(OH)3)
  • Orthoboric acid (H3BO3)
  • Orthoborsaeure
  • R57ZHV85D4
  • Super Flea Eliminator
  • The Killer
  • Three Elephant
  • trihydroxidoboron
  • Trihydroxyborane
  • Trihydroxyborone
  • V-Bella

Systematic names

  • boric acid

The EU re-evaluation programme

Every additive authorised in the EU before 20 January 2009 was put back through EFSA by Commission Regulation (EU) No 257/2010, and this one is named in it. What the Regulation required is below; whether the opinion has since been published is not something this site records.

  • To be evaluated by 31 December 2015. Named in Annex II, Part II, point 1 as “Boric acid”, among the additives given priority within its class.

Hazard reference values

EFSA and JECFA have both assessed Boric acid and their conclusions are not two comparable figures — EFSA records 0.16 mg/kg bw/day, JECFA not allocated. An acceptable daily intake is a reference value set by a committee, not a threshold above which harm begins. “Not specified”, “not limited” and “not allocated” are conclusions, not missing data, and they are shown in the words each body used rather than reduced to a number. See where the two committees differ.

Values set by assessing bodies. A body that has not set a value is not listed here.
TypeValuePopulationAssessed byOpinion
ADInot allocated—JECFA1961
ADI0.16 mg/kg bw/dayconsumersEFSAnot identified in the dataset

Evidence and how bodies read it

What assessing bodies concluded

Each conclusion is paraphrased in the body's own framing, from the published opinion linked beneath it. Where bodies differ, both stand; this site does not adjudicate between them or add a view of its own.

  1. EFSA 2013

    The ANS Panel concluded that boric acid (E 284) and borax (E 285) do not raise concern for genotoxicity, but noted adverse effects on the male reproductive system in animal studies. It established a group ADI of 0.16 mg boron/kg bw/day and concluded that regular exceedance of the ADI from the authorised use in sturgeon eggs (caviar) was unlikely.

    Source document

Common questions

Assembled from what is above, in the words the questions are usually asked in. Each answer is the same statement the relevant section makes, with the same citations behind it.

What is E 284?
E 284 is Boric acid. Boric acid is permitted in the EU as a preservative in exactly one food: sturgeon caviar. It was once a common preservative and was withdrawn from everything else; caviar is the exception.
What is Boric acid used for in food?
It is listed as a lubricant or release agent — the role the US assigns it. This page shows every function each regulator records, with the citation for each.
Where is Boric acid permitted?
Of the seven regulators this site reads, the EU and Great Britain permit it. Each permission is for named foods at named levels, not a blanket one; the table on this page gives them with citations.
Is Boric acid vegan?
Yes. Boric acid is not derived from animals, and is suitable for vegetarians. This page says what it is made from and how.

Sources for this page

  • eu retrieved 2026-10-18
  • gb retrieved 2026-10-18
  • euspecs retrieved 2026-10-18

Full licence terms and publisher details on Sources. How this page is built and updated: Method.

Machine-readable: a JSON record of this additive is given on request —how to ask for access.

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