The experience of food tasting different or bland during illness is a common and frustrating phenomenon.

This change in taste perception can diminish appetite and affect nutrition during a time when the body most needs nourishment.

The Interconnectedness of Taste and Smell

Taste perception is not solely reliant on the tongue’s taste buds; it is intricately linked with the sense of smell. When eating or drinking, the brain synthesizes signals from both taste receptors on the tongue and olfactory receptors in the nose to create the perception of flavor. The five basic tastes—sweet, sour, salty, bitter, and umami—represent chemical detections on the tongue, but the full complexity of flavor relies heavily on olfactory input.

When individuals become sick, particularly with conditions causing nasal congestion or inflammation such as colds or the flu, the nasal passages can become swollen and blocked with mucus. This congestion reduces the ability of odor molecules from food to reach the olfactory receptors in the nose, thus severely impairing smell.

Since smell contributes predominantly to flavor perception, this leads to foods tasting muted or different altogether. Essentially, the brain receives incomplete sensory input, and the gustatory experience becomes diminished or distorted.

Inflammatory Responses and Sensory Effects

Beyond mere blockage, infection triggers an inflammatory response in the body. This inflammation can extend to the mucous membranes inside the nasal cavity and mouth, altering the local environment around sensory receptors. Inflammation may also affect nerve signaling pathways that carry taste and smell information to the brain. Some scientific studies even suggest that certain proteins released during immune activation might directly change how taste receptors function.

Viral and Bacterial Impacts on Taste Receptors

Specific pathogens can directly affect taste buds or related epithelial cells in the mouth. For example, SARS-CoV-2, the virus causing COVID-19, is known to bind to ACE2 receptors present on cells in the cavity, including taste buds. This interaction may cause temporary taste loss or distortion (dysgeusia) even in the absence of a congested nose.

Other common respiratory viruses and bacteria may similarly disrupt the normal renewal cycle of taste buds or damage nerves involved in taste. While most people regain normal taste function as they recover, some infections can cause longer-lasting or even permanent taste changes, especially if the inflammation persists or nerve damage occurs.

Medication and Treatments That Influence Taste

During illness, many patients receive medications such as antibiotics, antivirals, decongestants, or pain relievers. Some of these drugs have side effects that include taste alteration. Antibiotics, for example, may cause a metallic taste, whereas decongestants can dry out the nasal passages and mouth, further reducing flavor perception. Understanding these medication effects is important for managing patient expectations and selecting options to minimize taste disturbance.

Psychological and Nutritional Considerations

Taste changes during illness are more than a physical inconvenience—they influence appetite and nutrient intake. When food becomes unappetizing due to altered taste, individuals may eat less or avoid certain foods, impacting recovery. Recognizing the temporary nature of these changes and using flavorful alternatives that stimulate unaffected taste sensations (like warmer, spicier, or sour foods) can help maintain caloric and nutrient consumption.

According to Dr. Edward Kuan, tongue and smell disorders specialist, taste changes may stem from infections, medications or other medical conditions. He notes that illnesses such as the common cold or flu often reduce smell — which is tightly linked with taste — and that inflammation or nerve damage in the mouth during illness can also affect taste‑bud function.

Taste changes when sick primarily because of the close relationship between taste and smell, where nasal congestion blocks odor perception, and inflammation affects sensory receptors and nerve pathways. Specific infections can directly impair taste bud function, and medications used during illness may exacerbate taste alterations. Although unpleasant, these changes are generally temporary and reversible as health returns, emphasizing the importance of supportive care and nutritional strategies during illness.