Bisabolol
In plain terms
A soothing, anti-inflammatory active found in chamomile, used to calm redness and irritation. It is gentle and well tolerated, with a small caveat for people allergic to chamomile or ragweed.
What the evidence shows
Bisabolol is a soothing compound that makes up much of the calming power of chamomile, where it can be nearly half of the flower oil; most cosmetic bisabolol is now made to a consistent purity rather than extracted. It works as an anti-inflammatory and anti-irritant, quieting the pathways that drive redness, which is why it shows up in products for sensitive and reactive skin. Its safety record is good. The US cosmetic-ingredient panel judged it safe as used, the US food agency lists it as generally recognized as safe for its low toxicity, and dermal studies found no sensitization or light-triggered reaction, with human patch testing at high levels coming back clean. The one caveat is botanical: because it comes from the daisy family, people already allergic to chamomile, ragweed, or other Asteraceae plants can cross-react, so a patch test makes sense for them. For everyone else it is one of the gentler soothing actives, with no hormone, cancer, or contamination concern attached.
On the label
Listed as bisabolol or alpha-bisabolol, usually in the soothing part of a sensitive-skin serum or cream. If you react to chamomile, ragweed, or daisies, patch test first, since it shares that plant family; otherwise it is a gentle addition.