Diazolidinylurea(in 13,654 products)
1. Antimicrobial Preservative - Actively kills and inhibits the growth of unwanted microorganisms which may be harmful.
2. Drug / Medicine - Used to treat, alleviate, cure or prevent sickness. As officially declared by a governmental drug/medicine regulatory body
3. Preservative - Prevents and inhibits the growth of unwanted microorganisms which may be harmful
May release Formaldehyde under aqueous conditions, such as contacting with water or in humid conditions.
Please see 'Formaldehyde' for further details.
- 150ppm of formaldehyde can be recovered from shampoos using 0.1% diazolidinylurea and up to 740ppm can be recovered from a concentration of 0.8%. In protein-based shampoos, the formaldehyde recovered is lower as formaldehyde can be complexed (binded) to the protein, preventing its release.
- As for environmental impacts, diazolidinylurea can also be used to promote tissue healing in "salt water, tropical, and cold water fish". 
- In a separate study, diazolidinylurea has proven its effectiveness as an anti-fungal and anti-bacterial agent, especially when combined with other antimicrobial compounds such as N-chloramines and parabens. 
1. PubChem: https://pubchem.ncbi.nlm.nih.gov/compound/62277
2. Investigation on formaldehyde release from preservatives in cosmetics (Int J Cosmet Sci. 2015 Oct;37(5):474-8. doi: 10.1111/ics.12212)
3. Final Report on the Safety Assessment of Diazolidinyl Urea (Int. J. Toxicol. 1990 March;9(2):229-245. doi: 10.3109/10915819009078735)
4. Antimicrobial Activities of N-Chloramines and Diazolidinyl Urea (Appl. Environ. Microbiol. Feb 1985, 49 (2) 370-373)
1. EU CosIng Annex V, PRESERVATIVES ALLOWED IN COSMETIC PRODUCTS 
- Ref: V/46
2. Cosmetic Ingredient Review
- Diazolidinyl Urea
Safety and Hazards (UN GHS):
1. May cause an allergic skin reaction (H317)
2. Causes serious eye irritation (H319)
3. Harmful to aquatic life with long lasting effects (H412)
Potential Health Concerns For:
1. Dermatitis, Allergic Contact (PubMed ID:16426289)
2. Dermatitis, Atopic (PubMed ID:15218738)
3. Eczema (PubMed ID:16426289)
4. Erythema (PubMed ID:16426289)