The aim of this study discovers the analgesic and anti- inflammatory effects of diphenhydramine in mice that result from
formaldehyde injected 1% concentration s/c in right planter of adult mice after 15 minutes of diphenhydramine injection I/M in
comparison with control group which it injected with normal saline. Intramuscular injection of diphenhydramine in mice at 1,
2 mg/kg respectively caused analgesia and anti- inflammatory effect that result from pain induced by formaldehyde through
significant decrease in licking numbers of formaldehyde injected foot, significantly increase its onset of licking, significant
decrease the time elapsed of licking and significant decrease in depth of planter injected foot in comparison with control group.
The data of this study suggested that diphenhydramine has anti- inflammatory effect and of analgesic effect in doses 1, 2 mg/
kg I/M in adult mice.