Why do some smells make you nauseous?

Some smells can trigger nausea due to the brain's response to certain odors that may be associated with danger or toxicity. The olfactory system is closely linked to the limbic system, which governs emotions and memories, leading to a strong reaction to unpleasant or unfamiliar smells. Additionally, individual sensitivity to certain scents can vary, causing some people to feel nauseous where others do not. Factors like past experiences, cultural associations, and even pregnancy can also influence how we react to certain smells.