 These include interleukin 12 (IL-12), interferon gamma (IFNγ) and interleukin 10 (IL-10).Some pharmacological studies such as on tolfenamic acid and "Opuntia ficus-indica" (OFI) have also indicated an involvement of the immune system.These studies suggest that the presence and severity of hangover symptoms can probably be reduced by administration of a cyclooxygenase inhibitor such as aspirin or ibuprofen.