Abstract Fullerenes are a class of novel carbon allotropes being investigated potential therapeutic agents; here we report a biological function for C70-based fullerenes derivatized with inositol (C70-I). Human Mast Cells (MC) were harvested from tissue and incubated with C70-based fullerenes derivatives. Next, mediator release (cytokine and beta-hexosamindase) or protein levels (Western blot or immunoprecipitation) was measured. This derivative induced significant increases in the gene and protein expression of human mast cell dual-specificity phosphate one (DUSP1); master regulator of the corticosteroid response in asthma. This increase in FCϵRI-induced DUSP1 expression resulted in the dephosphorylation of mitogen-activated protein kinases and acted synergistically with corticosteroids to diminish mediator release from MC. The increase in DUSP1 protein expression was due in part on the ability of C70-I to prevent the ubiquitination and degradation of DUSP1. These findings identify yet another potential application of functionalized fullerenes as a way to increase the efficacy of corticosteroids or use as an anti-inflammatory through the control of DUSP1.