Why can't we taste when we have a cold

How taste and olfaction work

In earlier posts we discussed how closely smell and taste work together. This relationship becomes obvious when you catch a cold and notice that food and drinks lose much of their flavour. The cause is not a failure of the taste buds, but a disruption of the olfactory system, which plays a major role in how we perceive what we eat and drink.

When you have a cold , the infection triggers inflammation in the nasal passages. The lining of the nose swells, airflow is reduced, and mucus production increases. These changes physically block odour molecules from reaching the olfactory receptors at the top of the nasal cavity. In some cases, the virus may also irritate or impair receptors themselves, temporarily reducing their sensitivity.

Both pathways of smell are affected:

Orthonasal olfaction (smelling through the nostrils) declines because airflow is restricted.

Retronasal olfaction (aroma released from the mouth during eating and drinking) weakens because inflammation and mucus prevent odour molecules from travelling up towards the olfactory region.

Since most of what we perceive as flavour comes from smell rather than taste, this obstruction leads to a noticeably muted experience. Sweetness, acidity, bitterness, saltiness, and umami are still detectable, but without aroma they feel flat and incomplete.

The good news is that these changes are temporary. As inflammation decreases and normal airflow returns, both orthonasal and retronasal smelling recover, restoring the full sensory profile of food and drink. This process highlights how dependent taste is on the ability of the nose to function properly, and why something as simple as a cold can have such strong effects on flavour perception.