Answer · confidence: partial
Why was red dye 3 banned only partly in 1990 but fully in 2025?
Research question: What specific toxicological data did the FDA rely on in its 1990 partial erythrosine action, and why was the food restriction narrower than the 2025 full ban?
The records show that in 1990 FDA declined to extend the provisional listing of FD&C Red No. 3 for cosmetics and externally applied drugs, based on thyroid neoplasia found in rat carcinogenicity studies 9. The verified facts do not explicitly identify the specific rat data FDA used for that decision. They do note that the key animal data behind later conclusions came from Borzelleca et al.'s 1987 compilation of two rat studies 14, and a 1988 study reported a 91% thyroid tumor incidence in partially thyroidectomized rats given Red 3 and DHPN 4, but nothing links that study to the 1990 action. The food restriction was narrower because the 1990 action did not revoke the permanent 1969 listing for food and ingested drugs 11. The 2025 order went further by revoking authorized uses in both food, including dietary supplements, and ingested drugs 19, and FDA said the Delaney Clause required this because cancer was a known effect in male rats, even though it found the dye not relevant to humans 21. The newest fact is dated January 16, 2025, about 21 months before October 2026 1719.
Checked 2026-10-22. Only documented and supported facts are used.
Dig deeper on this questionSources
[1] supported
In rats, Red 3 and Red 105 significantly promoted thyroid tumor development only in thyroidectomized animals, not in non-thyroidectomized ones.
"Red 3 and Red 105 significantly promoted the development of thyroid tumors in thyroidectomized rats given DHPN, but had no significant effect in non‐thyroidectomized rats."The Promoting Effects of Food Dyes, Erythrosine (Red 3) and Rose Bengal B (Red 105), on Thyroid Tumors in Partially Thyroidectomized N‐Bis(2‐hydroxypropyl)‐ nitrosamine‐treated Rats (1988)
[2] supported
Erythrosine (Red 3) was largely replaced in most food applications because of its negative health effects.
"completely replacing amaranth (Red 2) and also replacing erythrosine (Red 3) in most applications due to the negative health effects of those two dyes."Allura Red AC
[3] supported
The seven straight colors approved under the 1906-era Food Inspection Decision 76 included erythrosine, which the document names as FD&C Red No. 3.
"The seven dyes were Ponceau 3R (FD&C Red No. 1), amaranth (FD&C Red No. 2), erythrosine (FD&C Red No. 3), indigotine (FD&C Blue No. 2), light green SF (FD&C Green No. 2), naphthol yellow 1 (FD&C Yellow No. 1), and orange 1 (FD&C Orange No. 1)."Food coloring
[4] documented
The thyroid tumor incidence was 91% in partially thyroidectomized rats given Red 3 and DHPN.
"The incidence of thyroid tumors was 91% in rats with partial thyroidectomy, Red 3 and DHPN"The Promoting Effects of Food Dyes, Erythrosine (Red 3) and Rose Bengal B (Red 105), on Thyroid Tumors in Partially Thyroidectomized N‐Bis(2‐hydroxypropyl)‐ nitrosamine‐treated Rats (1988)
[5] supported
The FDA banned amaranth (Red 2) for carcinogenicity in 1976, and Allura Red AC was developed in 1971 as its replacement.
"which the FDA banned for carcinogenicity in 1976"Allura Red AC
[6] documented
Serum TSH was 5.5±3.1 ng/ml in partially thyroidectomized rats given Red 3 and DHPN, compared with 1.5±0.5 ng/ml in rats given DHPN without a dye.
"Serum TSH was 5.5±3.1 ng/ml in rats with partial thyroidectomy, Red 3 and DHPN, 2.1 ± 2.2 ng/ml in rats with partial thyroidectomy, Red 105 and DHPN, and 1.5±0.5 ng/ml in rats with partial thyroidectomy and DHPN."The Promoting Effects of Food Dyes, Erythrosine (Red 3) and Rose Bengal B (Red 105), on Thyroid Tumors in Partially Thyroidectomized N‐Bis(2‐hydroxypropyl)‐ nitrosamine‐treated Rats (1988)
[7] supported
The rat study fed Red 3 and Red 105 at 4% of the basal diet for 19 weeks, starting at week 2.
"Red 3 and Red 105 were used at 4% in the basal diet and were administered for 19 weeks from week 2 to 20."The Promoting Effects of Food Dyes, Erythrosine (Red 3) and Rose Bengal B (Red 105), on Thyroid Tumors in Partially Thyroidectomized N‐Bis(2‐hydroxypropyl)‐ nitrosamine‐treated Rats (1988)
[8] supported
The document cites a 2025 HHS and FDA announcement about phasing out petroleum-based synthetic dyes in the food supply.
""HHS, FDA to Phase Out Petroleum-Based Synthetic Dyes in Nation's Food Supply""Allura Red AC
[9] supported
In 1990, FDA declined to extend the provisional listing of FD&C Red No. 3 for cosmetics and externally applied drugs, based on thyroid neoplasia found in rat carcinogenicity studies.
"based on thyroid neoplasia in rat carcinogenicity studies, which terminated this listing"Federal Register :: Color Additive Petition From Center for Science in the Public Interest, et al.; Request To Revoke Color Additive Listing for Use of FD&C Red No. 3 in Food and Ingested Drugs
[10] supported
In a rat study, feeding 4% erythrosine in the diet induced hyperthyroidism regardless of whether the dye was purified or sodium iodine was added.
"ER at 4 % in the diet induced hyperthyroidism, irrespective of purification and/or additional sodium iodine administration."Review of the Toxicity of the Dyes Quinoline Yellow, Erythrosine and Patent Blue V and Evaluation of their Suitability as Excipient in Medicinal Products for Oral Use (2019)
[11] supported
The 1990 FDA action did not revoke the permanent 1969 listing for FD&C Red No. 3 in food and ingested drugs, which is why the food restriction was narrower.
"The decision did not revoke the existing permanent listing for food and ingested drugs from 1969."Federal Register :: Color Additive Petition From Center for Science in the Public Interest, et al.; Request To Revoke Color Additive Listing for Use of FD&C Red No. 3 in Food and Ingested Drugs
[12] supported
In a study of thyroidectomised rats treated with the carcinogen DHPN, thyroid tumours occurred in 91% of rats on an erythrosine diet versus 64% of rats on the regular diet.
"In DHPN-treated and thyroidectomised rats, thyroid tumours were observed in 91 % of rats on ER-diet compared to 64 % of rats on regular diet."Review of the Toxicity of the Dyes Quinoline Yellow, Erythrosine and Patent Blue V and Evaluation of their Suitability as Excipient in Medicinal Products for Oral Use (2019)
[13] supported
The only carcinogenicity evidence for erythrosine comes from non-guideline studies, since no guideline-compliant carcinogenicity study had been performed.
"Guideline-compliant carcinogenicity studies have not been performed with erythrosine."Opinion ON CI 45430 Erythrosine (2010)
[14] supported
The key animal data behind later conclusions came from Borzelleca et al.'s 1987 compilation of two separate chronic toxicity and carcinogenicity studies in rats.
"a compilation of two separate chronic toxicity and carcinogenicity studies"Federal Register :: Color Additive Petition From Center for Science in the Public Interest, et al.; Request To Revoke Color Additive Listing for Use of FD&C Red No. 3 in Food and Ingested Drugs
[15] supported
Sodium iodine supplementation alone did not cause hyperthyroidism in the rats, so the thyroid effect was specific to erythrosine.
"No hyperthyroidism was observed in the group receiving diet fortified with sodium iodine only."Review of the Toxicity of the Dyes Quinoline Yellow, Erythrosine and Patent Blue V and Evaluation of their Suitability as Excipient in Medicinal Products for Oral Use (2019)
[16] documented
The 1990 JECFA evaluation assigned erythrosine the same acceptable daily intake of 0 to 0.1 mg/kg body weight that the EU's SCF had set in 1987, after re-evaluating its safety.
"same ADI was assigned by the Joint WHO/FAO Expert Committee for Food Additives (JECFA, 1990), following a re-evaluation of the safety of this colorant."Opinion ON CI 45430 Erythrosine (2010)
[17] documented
FDA's 2025 finding is that FD&C Red No. 3 can induce cancer in male rats through a rat-specific hormonal mechanism.
"FDA finds that FD&C Red No. 3 can induce cancer in male rats, through a rat specific hormonal mechanism."Federal Register :: Color Additive Petition From Center for Science in the Public Interest, et al.; Request To Revoke Color Additive Listing for Use of FD&C Red No. 3 in Food and Ingested Drugs
[18] supported
Thyroid effects were the main toxicological concern, and the reviewers derived NOAELs (no-observed-adverse-effect levels) for thyroid effects because a genotoxic mechanism was judged unlikely, pointing to an indirect pathway for the thyroid tumours seen in rats.
"Therefore, the derivation of NOAELs for thyroid effects is justified."Opinion ON CI 45430 Erythrosine (2010)
[19] supported
The 2025 order revoked the authorized uses of FD&C Red No. 3 in both food (including dietary supplements) and ingested drugs, going beyond the 1990 action.
"FDA is revoking the authorized uses in food and ingested drugs of FD&C Red No. 3 in the color additive regulations."Federal Register :: Color Additive Petition From Center for Science in the Public Interest, et al.; Request To Revoke Color Additive Listing for Use of FD&C Red No. 3 in Food and Ingested Drugs
[20] supported
The 2025 Red No. 3 revocation relied on data from a 2022 color additive petition, which included two chronic feeding studies in which male rats given high doses developed cancerous tumors through a rat-specific hormonal mechanism.
"Data provided in a 2022 color additive petition submitted to the FDA included two chronic feeding studies showing that male rats exposed to high levels of FD&C Red No. 3 developed cancerous tumors via a rat-specific hormonal mechanism."FDA to Revoke Authorization for the Use of Red No. 3 in Food and Ingested Drugs
[21] supported
Despite the finding that the dye is not relevant to humans, FDA said the Delaney Clause required revoking the authorization because cancer was a known effect in male rats.
"However, since cancer is a known effect in male rats upon ingestion of the dye, application of the Delaney Clause requires that the authorization for FD&C Red No. 3 be revoked."FDA to Revoke Authorization for the Use of Red No. 3 in Food and Ingested Drugs