Taste of Inhalational Anesthetics

Inhalational anesthetics are a cornerstone of modern anesthesia, widely used for inducing and maintaining unconsciousness during surgical procedures. While their primary role is to suppress pain perception and awareness, these agents also affect the senses of taste and smell. Although taste is not the primary concern when administering inhalational anesthetics, patients often report distinct sensory experiences related to their exposure, which can influence their comfort and overall experience.

Taste perception is primarily influenced by the interaction of molecules with taste receptors on the tongue. However, inhalational anesthetics do not enter the oral cavity in the same way as ingested substances. Instead, they interact with the olfactory system, which significantly influences taste perception. The volatile nature of these agents allows them to dissolve in mucosal linings of the mouth and upper airway, where they can be detected as flavors.

Although inhalational anesthetics do not directly stimulate taste buds, patients under anesthesia or emerging from it frequently report transient taste disturbances. Some describe a lingering metallic or chemical taste, while others experience a temporary alteration in their ability to perceive flavors. These effects may be due to the interaction of anesthetic gases with oral and nasal mucosa or changes in saliva composition during exposure.

The most commonly used agents include nitrous oxide, isoflurane, desflurane, and sevoflurane. Each of these inhalational anesthetics has a unique chemical structure that contributes to its sensory characteristics.

Nitrous oxide, also known as “laughing gas,” is generally described as having a slightly sweet odor and taste at room temperature and pressure ¹. This makes it more acceptable to patients, particularly in dental and pediatric settings ^2,3. In contrast, isoflurane is a non-flammable volatile anesthetic which carries a strong, pungent odor that makes it less pleasant to use for inhalational induction of general anesthesia ⁴. Finally, the third-generation volatile anesthetic agent desflurane has a pungent odor and is a respiratory irritant ^5,6, while sevoflurane, another third-generation volatile anesthetic agent, is often described as having a sweet, slightly fruity odor, which translates into a mild and relatively tolerable taste ^7,8.

Research suggests that patients who undergo mask induction, particularly children, are more likely to notice the taste and smell of anesthetic gases. In pediatric anesthesia, efforts have been made to mask these sensations with flavored masks or preconditioning techniques ^9,10.

Although typically a minor concern, the taste of inhalational anesthetics, can influence patient experience and comfort. For some individuals, an unpleasant taste may contribute to preoperative anxiety or postoperative nausea ^11,12. Ultimately, while the taste of inhalational anesthetics is not a primary focus of anesthetic care, understanding their sensory properties can help improve patient experience, particularly for those sensitive to taste and smell. Strategies should be employed to mitigate any undesired effects whenever necessary.

References

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2. Gupta, N., Gupta, A. & Narayanan M R, V. Current status of nitrous oxide use in pediatric patients. World J Clin Pediatr 11, 93–104 (2022). DOI: 10.5409/wjcp.v11.i2.93
3. Veger, M. L., van Iterson, J., Bakx, R. & Ridderikhof, M. L. The Role of Nitrous Oxide in Minor Pediatric Procedures in the Emergency Department: A Systematic Review. Journal of Pediatric Surgery 59, 1154–1162 (2024). DOI: 10.1016/j.jpedsurg.2023.12.026
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6. Khan, J., Patel, P. & Liu, M. Desflurane. in StatPearls (StatPearls Publishing, Treasure Island (FL), 2025).
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8. Edgington, T. L., Muco, E. & Maani, C. V. Sevoflurane. in StatPearls (StatPearls Publishing, Treasure Island (FL), 2025).
9. Healthcare, G. E. Pediatric anesthesia induction | Clinical View. https://clinicalview.gehealthcare.com/article/pediatric-anesthesia-induction-debate-over-techniques-and-how-keep-little-patients-calm (2023).
10. Intersurgical – Scented anaesthetic face masks. https://www.intersurgical.com/products/anaesthesia/scented-anaesthetic-face-masks.
11. openanesthesia. Preoperative Anxiety in Children. OpenAnesthesia https://www.openanesthesia.org/keywords/preoperative-anxiety-in-children/.
12. Dave, N. M. Premedication and Induction of Anaesthesia in paediatric patients. Indian J Anaesth 63, 713–720 (2019). DOI: 10.4103/ija.IJA_491_19