Table 2 Some common ingredients in natural repellents that may be hazardous. Reproduced with permission from [63]
From: Plant-based insect repellents: a review of their efficacy, development and testing
Common Name | Scientific Name | Safe Concentration | Hazard |
|---|---|---|---|
Anise | Pimpinella anisum | 3.6% | Based on 0.11% methyl eugenol; carcinogen |
Basil | Ocimum sp | 0.07% | Based on 6% methyl eugenol; carcinogen |
Bergamot | Citrus aurantium bergamia | 0.4% | Sensitising and phototoxic; skin irritant |
Cajeput | Melaleuca alternifolia | 0.004% | Based on 97% methyl eugenol; carcinogen |
Cedar | Chamaecyparis nootkatensis | 1% | Likely allergenic contaminants if nootkatone not 98% pure |
Cassia | Cinnamonium cassia | 0.2% or 9% | Sensitising skin irritant |
Citronella | Cymbopogon nardus | 2% | Safety is controversial; based on 0.2% methyl eugenol or 1.3% citral; sensitising skin irritant |
Citronella (Java) | Cymbopogon winterianius | 2% | Based on 0.2% methyl eugenol; carcinogen |
Citrus oils | Citrus sp | 16-25% | Based on 0.005%-0.0025% bergapten; phototoxic skin irritant |
Clove | Syzyguim aromaticum | 0.5% | Based on 92% eugenol; sensitising skin irritant |
Fever tea, lemon bush | Lippia javanica | 2% | Based on 5% citral in related species; sensitising skin irritant |
Geranium | Pelargonium graveolens | 6% | Based on 1.5% citral; sensitising skin irritant |
Ginger | Zingiber sp | 12% | Based on 0.8% citral; sensitising skin irritant |
Huon oil, Macquarie pine | Langarostrobus franklini | 0.004% | Based on 98% methyl eugenol; carcinogen |
Lemongrass | Cymbopogon citratus | 0.1% | Based on 90% citral; sensitising skin irritant |
Lime | Citrus aurantifolia | 0.7% | Phototoxic skin irritant |
Litsea | Litsea cubeba | 0.1% | Based on 78% citral; sensitising skin irritant |
Marigold | Tagates minuta | 0.01% | Phototoxic skin irritant |
Mexican tea, American wormseed | Chenopodium ambrosioides | Prohibited | Toxic |
Mint | Mentha piperata and spicata | 2% | Based on 0.1% trans-2-hexenal; sensitising skin irritant |
Nutmeg | Myristica fragrans | 0.4% | Based on 1% methyl eugenol; carcinogen |
Palmarosa | Cymbopogon martini | 16% | Based on 1.2% farnesol; sensitizing skin irritant |
Pennyroyal | Mentha pulegium or Hedeoma pulegioides | Prohibited | Toxic |
Pine | Pinus sylvestris | Prepare with antioxidants | Oxidation creates phototoxic skin irritants |
Rosemary | Rosemarinus officinalis | 36% | Based on 0.011% methyl eugenol; carcinogen |
Rue | Ruta chalepensis | 0.15% | Based on presence of psoralenes; phototoxic skin irritant |
Thyme | Thymus vulgaris | 2% | Based on 0.1% trans-2-hexenal; sensitising skin irritant |
Violet | Viola odorata | 2% | Based on 0.1% trans-2-hexenal; sensitising skin irritant |
Ylang-ylang | Canagium odoratum | 2% | Based on 4% farnesol; sensitizing skin irritant |