Mixed lymphocyte responses assays were conducted at 25.0 and 250.0 μg/mL of the crude ethanolic extract of Boehmeria jamaicensis Urb (coded as BJE) using peripheral lymphocytes obtained from individuals suffering from the common cold after four days of infection and from healthy individuals (without the common cold infection). At a concentration of 25 ug/mL, gamma interferon (IFN-γ) was increased by 24.03 fold and interleukin 4 (IL-4) by 1.71 fold for the cells obtained from individuals with the common cold (Group A). The extract suppressed IFN-γ by 8.3% while IL-4 was stimulated by 9.90 fold from peripheral lymphocytes obtained from healthy individuals (Group B). Gamma interferon was suppressed at 250 μg/mL while IL-4 was elevated by 1.86 fold for cells obtained from individuals suffering from the common cold (Group A). In conclusion, BJE could have implications for the treatment of the common cold.