Despite research efforts to unravel the role of naturally occurring deep eutectic solvents (NADESs) in living cells, there are still many questions left unanswered. The proposed hypothesis about the role of NADESs in cryopreservation and resistance of cells motivated us to investigate whether DESs might possess chaperoning activity. Accordingly, here, the chaperone‐like activity of a well‐known DES, urea‐choline chloride DES (UC), on a model protein, lysozyme, has been evaluated. The results showed that UC DES was not only capable of suppressing lysozyme aggregation almost completely, but also efficiently enhanced the refolding yield of the denatured enzyme by nearly 95%, thereby suggesting the chaperoning potency of DESs. The refolding promotion of lysozyme was also verified through fluorescence study. The results may introduce DESs as new generation chaperones and shed light on their role in cell resistance under stress conditions.

No abstract