Is Zinc PhenolSulphonate (ZPS) 0.8% w/v + Mentha Oil 0.3% v/v + Clove Oil 0.3% v/v + Phenol 0.2% w/v + Glycerine (Glycerin) safe during the first trimester of pregnancy?

Safety of Zinc Phenolsulfonate Combination Mouthwash in First Trimester

This topical oral formulation containing zinc phenolsulfonate, mentha oil, clove oil, phenol, and glycerine should be used with caution in the first trimester, and only if the benefit clearly outweighs potential risks, particularly due to the phenol component.

Key Safety Considerations by Component

Phenol (0.2% w/v) - Primary Concern

• The FDA drug label for phenol explicitly states: "If pregnant or breast-feeding, ask a health professional before use" 1
• Phenol requires medical consultation before use during pregnancy, indicating uncertain safety profile 1
• The concentration (0.2%) is within typical topical oral care ranges, but systemic absorption from oral mucosa can occur 1

Zinc Phenolsulfonate (0.8% w/v) - Generally Safe

• Zinc is considered safe throughout pregnancy and is recommended as part of routine prenatal supplementation at doses of 8-15 mg daily 2
• Zinc phenolsulfonate has been confirmed safe as a cosmetic ingredient in current practices of use 3
• A retrospective study documented 282 pregnancies where 118 women took zinc throughout pregnancy with favorable maternal and fetal outcomes 2
• The topical oral application results in minimal systemic absorption compared to oral supplementation 4, 3

Mentha Oil (0.3% w/v) - Limited Safety Data

• Peppermint oil safety assessment focused on cosmetic use at concentrations ≤0.2% in leave-on formulations and ≤3% in rinse-off products 5
• The concentration (0.3%) exceeds typical leave-on cosmetic use, though this is a rinse formulation 5
• Critical concern: Pulegone content in mentha oil must be ≤1% due to hepatotoxicity and neurotoxicity 5
• No specific pregnancy safety data available for oral mucosal application 5
• Menthol (major component) can enhance penetration of other ingredients, potentially increasing systemic absorption of phenol 5

Clove Oil (0.3% w/v) - Insufficient Pregnancy Data

• Clove essential oil contains eugenol (≥50%), eugenyl acetate, β-caryophyllene, and α-humulene 6
• While widely used in food and cosmetic industries, specific pregnancy safety data for topical oral application is lacking 6
• No documented teratogenic effects, but absence of evidence is not evidence of safety 6

Glycerine - Safe

• Glycerine is generally recognized as safe during pregnancy with extensive use history 2

Clinical Decision Algorithm

First Trimester Use:

1. Avoid routine use - defer to safer alternatives (salt water rinses, pregnancy-safe mouthwashes without phenol)
2. If symptomatic relief is essential:
   • Consult with obstetrician before initiating use 1
   • Verify mentha oil pulegone content is ≤1% 5
   • Use minimal amount and avoid swallowing 1
   • Limit duration to shortest period necessary (≤2 days) 1
   • Discontinue immediately if any adverse symptoms develop 1

Second and Third Trimesters:

• Risk-benefit ratio may be more favorable after organogenesis is complete
• Same precautions regarding phenol consultation requirement apply 1

Critical Pitfalls to Avoid

• Do not assume topical oral products are systemically insignificant - oral mucosa has high absorption potential, especially with penetration enhancers like menthol 5
• Do not use if sore throat is severe or accompanied by fever, headache, nausea, or vomiting - these require medical evaluation, not self-treatment 1
• Do not exceed 2 days of use without medical consultation 1
• Do not use if the mentha oil source and pulegone content are unknown - pulegone causes cerebellar lesions and hepatotoxicity 5